I have been encountering the same error since I started using Unraid last year. I'm using an MSI B560i with an i5-10500T, and Unraid version 6.12.10.
As others have mentioned, even when the VM or Docker is not in use, the error still occurs.
If my VM, which uses the iGPU, is running, sometimes the entire Unraid system will crash. The only way to restore it is by doing a hard reboot.
I tried installing the Intel i915 SR-IOV plugin as suggested by tj0.
Although this stopped the error messages, it interferes with the i915 drivers, preventing the Intel GVT-g plugin from detecting my iGPU.
For those who just want to get rid of the error message, installing the SR-IOV plugin might help. However, this does not ultimately resolve the issue I guess.