Workaround in newest beta works for me, Aida64 now shows the number I expected.
I have tested it with a chess engine and assigned 16 cores (AMD 5950X, 16C, 32T) to it. So expected value is at least 50%.
Before the workaround I saw 30%. Now it is around 50-52%, so realistic to me. It also showed this value before Windows introduced the bug.
Windows Taskmanager shows 65% but that is too high for me beccause I didn't run other heavy programs.