Hello @botvot Thank you for alerting admins 
I thought I would help and share the review thread as issues with leaving stars were recently discussed there. New review system - Mega thread - #426 by Carla (there are a few comments from this comment down that explain what happens)
The team have mentioned that there are no glitches in the system, but if anyone accidentally leaves the wrong number of stars then Membership Services is always happy to help with that.