Wrong numbers of clients in "clients count by group"

SEP 12.1 RU2

In the report "clients count by group" the number of the clients is completely wrong (let me say, 2 or 3 times the real one).

If I check the group properties, the number is correct.

When I was on 12.1 RU1 MP1 I did not had this issue.

I've tried to repair the instllation of the SEPM. No way.
I've performed the dbvalidator. DB ok.