I upgraded to 6.12.3, especially because of the in the wiki mentioned IPv6 issues and now I have another, more annoying one.
If I try to start docker container with IPv6 addresses assigned to them, it will fail. 

I have my addresses to my IPv6 dockers assigned, Unraid showed them in the docker-settings page, and they are enabled, yet in the container Settings they are not showing up as they did with version. 6.12.2!

Unraid Network Settings of the Interface

Docker Settings Page

CLI output of the Interface

root@Z-Storage:~# docker network inspect br0.69
[
    {
        "Name": "br0.69",
        "Id": "5e996f4ad75df90ab9e36696dbd07f2095b09b601c835536bd961557fe2ab25f",
        "Created": "2023-07-16T22:18:30.879701979+02:00",
        "Scope": "local",
        "Driver": "macvlan",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": {},
            "Config": [
                {
                    "Subnet": "10.10.0.0/24",
                    "Gateway": "10.10.0.1",
                    "AuxiliaryAddresses": {
                        "server": "10.10.0.9"
                    }
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "ea72c624b391f6f0b2d5b067396bcec450acfb8e2f3c5d120769a73e0f710321": {
                "Name": "duplicati",
                "EndpointID": "8b9d474158493b514c860564df65f2eda086af1ccb93051fbd7852d07c950a7c",
                "MacAddress": "02:42:0a:0a:00:17",
                "IPv4Address": "10.10.0.23/24",
                "IPv6Address": ""
            },
            "ed1a29238b7f3fee6eb08558f328cb7abea2124004f7227d9aa1ba26850a83ba": {
                "Name": "ZH-Homepage",
                "EndpointID": "2d76bf03a3668e2daad7cc95265f93f3ed5aa2cc059d3a10a4c9a5a39026ff61",
                "MacAddress": "02:42:0a:0a:00:0c",
                "IPv4Address": "10.10.0.12/24",
                "IPv6Address": ""
            }
        },
        "Options": {
            "parent": "br0.69"
        },
        "Labels": {}
    }
]

It shows that IPv6 is disabled. This is not good, because my Services-Network depends on IPv6!

Container Settings Page

On the Right, wehre the yellow marking is, is normally the IPv6 network of the container listed, which is missing!

Diagnostics of 6.12.3

z-storage-diagnostics-20230716-2231.zip

They might be helpful.

Rollback to 6.12.2

Now I rolled back to 6.12.2 because I didn't want to change my configuration to IPv4! Here everything works as expected.

Here how the container settings should look like! I have a additional Unique Local Address-Network announced for static addressing within my homenet.

Here the same command as before but after the rollback.

root@Z-Storage:~# docker network inspect br0.69
[
    {
        "Name": "br0.69",
        "Id": "99be53f1356e2d70aacc6d91b414730f7d1dc14e70013de38b1f7a1113b55f28",
        "Created": "2023-07-16T22:48:51.744555435+02:00",
        "Scope": "local",
        "Driver": "macvlan",
        "EnableIPv6": true,
        "IPAM": {
            "Driver": "default",
            "Options": {},
            "Config": [
                {
                    "Subnet": "10.10.0.0/24",
                    "Gateway": "10.10.0.1",
                    "AuxiliaryAddresses": {
                        "server": "10.10.0.9"
                    }
                },
                {
                    "Subnet": "fd4f:71d8:b745:45::/64",
                    "Gateway": "fd4f:71d8:b745:45::1",
                    "AuxiliaryAddresses": {
                        "server6": "fd4f:71d8:b745:45:ae1f:6bff:fee4:7c6a"
                    }
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "2987cf58b40dc191c6637001f5ee904fe197cd3183dd59df4ad39253ccd25141": {
                "Name": "Redis",
                "EndpointID": "01adc1862ca009250c04e93ff66c19fdaf93249860c4fcb141cb6a3197d1294a",
                "MacAddress": "02:42:0a:0a:00:07",
                "IPv4Address": "10.10.0.7/24",
                "IPv6Address": "fd4f:71d8:b745:45:f773:520b:7496:e57e/64"
            },
            "3b4aeb62425f68755edb0d3bad2819afabbbdfe43021507e359b53a39ec28d87": {
                "Name": "Z-Media",
                "EndpointID": "8c5a5f744ddcd01d4db0e1ed492f8321efd763bca50e9a063bebecdb8a22d4cc",
                "MacAddress": "02:42:0a:0a:00:0b",
                "IPv4Address": "10.10.0.11/24",
                "IPv6Address": "fd4f:71d8:b745:45::f/64"
            },
            "41134e725c63f1a405efa8d54c330ba5ac273cbe52b5859794cc28df893d58b2": {
                "Name": "gotenberg",
                "EndpointID": "bbe9f5c14ea20f1a3095ba29b019d9ccae63f0addd1c8d8c03f792f46d130010",
                "MacAddress": "02:42:0a:0a:00:03",
                "IPv4Address": "10.10.0.3/24",
                "IPv6Address": "fd4f:71d8:b745:45:29b2:8dc3:3846:415d/64"
            },
            "417b46043e0e78bae32fff5885d2bbb7b5ca05d22bf0d07241735a7037392244": {
                "Name": "vaultwarden",
                "EndpointID": "8334e6c3ecf2c5c7ad06153c9b952baeb97492044f4c52cdb553ea02c59750d0",
                "MacAddress": "02:42:0a:0a:00:15",
                "IPv4Address": "10.10.0.21/24",
                "IPv6Address": "fd4f:71d8:b745:45:6263:70c2:74d3:55d/64"
            },
            "5679f9773f8ff78e69ce97de1c8307c780ad34798969b49447fc745f241e43db": {
                "Name": "z-cloud",
                "EndpointID": "30114e23d16bf480450e681cc79083585d92d3cc85191010cbf66cf5bf2ffe96",
                "MacAddress": "02:42:0a:0a:00:08",
                "IPv4Address": "10.10.0.8/24",
                "IPv6Address": "fd4f:71d8:b745:45::f572:9/64"
            },
            "5685f9ece498142d6f988bee988ee2ad6a75800e28ee3ed336f9a57f4ca6d890": {
                "Name": "maze-paperless-ngx",
                "EndpointID": "e3d87cf7e068e3e6143b105f604e00fb4bc6fcd4db817d215cc716ec0ed6a067",
                "MacAddress": "02:42:0a:0a:00:04",
                "IPv4Address": "10.10.0.4/24",
                "IPv6Address": "fd4f:71d8:b745:45:4d19:cabb:7c92:c4e8/64"
            },
            "8198827ded2d28cd7f477b97c83c6b14363506524474c81777186691f20d5bef": {
                "Name": "navidrome",
                "EndpointID": "231ff28551c7e69e9fbb9d2204a01f09548cdd2ea95ca221fb8e5fa6ad157722",
                "MacAddress": "02:42:0a:0a:00:18",
                "IPv4Address": "10.10.0.24/24",
                "IPv6Address": "fd4f:71d8:b745:45::18/64"
            },
            "bb9ebf7130fa486ec871fc9ce55f453dae36ed019c8f663a43a9a62a8a0b9f2b": {
                "Name": "paperless-ngx",
                "EndpointID": "2d65e207a6d465977563d7476a99fdbc6094573bc8bd52d34800de5b4314f67e",
                "MacAddress": "02:42:0a:0a:00:0a",
                "IPv4Address": "10.10.0.10/24",
                "IPv6Address": "fd4f:71d8:b745:45:cac5:7569:ffb4:c5c1/64"
            },
            "cc113428b4bca6e1d2d421c735f6d24bbfb3d4108036460b6e85d0019aa86e8c": {
                "Name": "postgresql15",
                "EndpointID": "85d39e1da2f2d87841391a75b41d64207538839e62cb64eac2f41d4ec25b5bcf",
                "MacAddress": "02:42:0a:0a:00:05",
                "IPv4Address": "10.10.0.5/24",
                "IPv6Address": "fd4f:71d8:b745:45:2128:752b:59d4:8f37/64"
            },
            "ced45afb96e45062744a60d0b48140642e824f2a8c7b02c9ac594f5b3359c086": {
                "Name": "Apache-Tika-Server",
                "EndpointID": "de6748aa63dad1ba44dffe7b8eb946e700e00b52d7e94915e59019c3b40a2323",
                "MacAddress": "02:42:0a:0a:00:02",
                "IPv4Address": "10.10.0.2/24",
                "IPv6Address": "fd4f:71d8:b745:45:5537:3bd0:2851:7d3/64"
            },
            "dc3b4e362af63719f79e1b5a674599a82eeed0ce0874921ddc6aa1601f1a49c2": {
                "Name": "MariaDB-Official",
                "EndpointID": "8270a1f63f2f0df3fb8226dbf15b39a0368208c37fb95cb733947fbad5fe37f4",
                "MacAddress": "02:42:0a:0a:00:06",
                "IPv4Address": "10.10.0.6/24",
                "IPv6Address": "fd4f:71d8:b745:45:5054:ff:fe61:3c3e/64"
            },
            "ea72c624b391f6f0b2d5b067396bcec450acfb8e2f3c5d120769a73e0f710321": {
                "Name": "duplicati",
                "EndpointID": "bc8c16c057a689a15719cf3ad158a5b0fe40fc2e552a3e723e3000d8c6c8325a",
                "MacAddress": "02:42:0a:0a:00:17",
                "IPv4Address": "10.10.0.23/24",
                "IPv6Address": "fd4f:71d8:b745:45::4/64"
            },
            "ed1a29238b7f3fee6eb08558f328cb7abea2124004f7227d9aa1ba26850a83ba": {
                "Name": "ZH-Homepage",
                "EndpointID": "a90db40c1047fa3adbe8f03a3d92f5dac639612f54a0cc5e1262971d4ef4e180",
                "MacAddress": "02:42:0a:0a:00:0c",
                "IPv4Address": "10.10.0.12/24",
                "IPv6Address": "fd4f:71d8:b745:45::2/64"
            }
        },
        "Options": {
            "parent": "br0.69"
        },
        "Labels": {}
    }
]

Please do not hesitate to ask questions if you have any and I hope this will be fixed soon.

Thank you for reading and have a lovely day.