I narrowed down the problem. It seems to happen when I join entities A and B, and B is a child of C and inheritance between B and C is "JOINED".

It also turned out that the error goes away if I upgrade to boot 3.1.1 (which uses hibernate 6.2.5).

Long story short: I probably bumped into an already fixed bug which is present in boot versions 3.0.0 - 3.1.0.

Anyway, the narrowed down minimal example is here

https://github.com/riskop/20251017_complicated_criteria_query_problem