Vocals Isolation and Reduction not working any more since upgrade to 3.0

The title says it. The vocals reduction and isolation effect changes absolutely nothing. I use this effect very often for my edits, so this is a real bummer.

That effect is always dependent on the source material …
https ://manual.audacityteam.org/man/vocal_reduction_and_isolation.html#limitations

I know, it was my most used effect. But since 3.x it just doesn’t work any more. It calculates, but does not do anything.

Ensure that you are using 3.0.2 and not 3.0.0.
You can get it here: https://www.audacityteam.org/download/