First day of week - not working?

I am doing something wrong… but what?
I had by default (system) Mo. as first day of the week - and correspondingly the energy graphs reseted on Mondays.
Actually I would like it to start on Sunday.
I changed the user settings and I also changed in my Mac settings… but the graphs still show the reset on Monday…
(yes - I did restart HA)

What am I missing please?

thanks