I get this error whenever I try to create a filtered deck, sorted by Relative Overdueness, that mentions a non-existing card or note-type.
Edit: actually I also get an error when existing card or note types are mentioned.
The issue seems to only occur if FSRS is enabled.
E.g.
Windows 10, Version 23.12 (4109d1e8)
Python 3.9.15 Qt 6.6.0 PyQt 6.6.0
No add-ons