And are you only seeing this after midnight? Between midnight and your 2am deadline, it’s still ‘today’ as far as your goal is concerned.
From that perspective, it’s the iOS app that is buggy, since it pays attention to clock time more than it sometimes should.
Talking about dates is really difficult, because our experienced day is usually delimited by periods of sleep, regardless of when clock midnight happens to fall.
Lots of people set their goal deadlines to be in the middle of their usual sleep period. It used to default to 4am for that reason. That backfires if you’re prone to skating the edge of your roads and are also willing to stay up until 4am to get them done.
I have the opposite annoyance with things like step trackers that decide that my just-after-midnight walk home from the tube station counts as steps taken on what, to me, is still tomorrow.
Even the (pretty decent) LifeCycle tracking app gets this wrong, despite doing the right thing with sleep that starts before midnight.