Trigger for "Individual" not working

CiviRules with trigger for individuals are not triggered anymore.

Steps to reproduce:

1. Add CiviRile with trigger "Individual is added".
2. Add contact of type "individual".
3. Go to "Manage CiviRules" and notice that "last triggered" is still empty.

It does work in 2.19, but not since 2.20 (including 2.22).

Trigger "Contact of any type is added" does still work. Don't know, if all triggers for individuals are effected. I've tested "added", "changed" and "deleted".

There were quite a lot of changes in release 2.20. I've tried to figure out which change causes this issue but without success so far.