5.6 crashes after disabling plugin

hi.
after disabling Control Rig plugin, the application crashes on startup:

Assertion failed: !TypeIndices.IsEmpty() [File:D:\build++UE5\Sync\Engine\Plugins\Runtime\RigVM\Source\RigVM\Private\RigVMCore\RigVMTemplate.cpp] [Line: 478]

my scene does not use any rig and I tested it even on a completely new, empty scene - same result.
I tried reinstalling 5.6 engine after (I think) I deleted all of its remaining files but it didn’t change anything.
I’m trying to publish an asset to Fab but they require that every unused plugin is disabled. recreating the scene in lower version would take A LOT of work…
does anyone have a better solution?
thank you