So, I looked at the appdata share
shareUseCache="prefer"
shareCachePool="cache"
# Share exists on disk1,disk2,disk3,cache_standard
And these are your cache pools
Jan 29 12:14:35 SINGTHESIS-NAS emhttpd: shcmd (43): mount -t btrfs -o noatime,space_cache=v2 /dev/sdb1 /mnt/cache_standard
Jan 29 12:14:35 SINGTHESIS-NAS emhttpd: shcmd (45): mount -t btrfs -o noatime,space_cache=v2 /dev/sdc1 /mnt/cache_vms
Net result here is that any new files for appdata are being written to the array because the "cache" pool does not exist at all. Once you change the settings to properly reflect which cache you want to actually use, disable all the services in settings and run mover. After it's done re-enable the services and you should be good to go.