If this counts as a bug: I'm in US Eastern time zone and the Simulator defaults to +5 hours for me. Maybe using GMT instead of the host Mac's time? (Easily changed manually in Playdate Settings.)
I think that was true both at first install of 1.9, and then again after the 1.9.1 update.
Also, the date (check it when Locked) is showing one day later than it should. (This I think may be new with 1.9.1.) I don't see a way to change that in Settings.