Adding a "me too" to this issue, which came about following a power outage. Unraid 6.8.3 diags attached.
I am running a UPS, and as far as i can tell the server shut down cleanly (parity was still valid when it came back up).
Everything seemed normal, shares and docker all ok, except for when my VM didn't autostart. It flagged an error when i manually started it, that I was missing my second vdisk image that i have on an array only share (for games). The vdisk Windows is installed on, is on cache.
I commented that second vdisk out from the xml and the VM booted fine, though windows did have to do some disk checking.
Let me know if i can provide any more info.
tower-diagnostics-20200430-2128.zip