mine went up to 45 minutes last night. ridiculous. does it on both my series 5's, and my Ultra.
battery life has also tanked bigtime. my Ultra used to last two days, now i'm finishing day one in the 30% range when I used to finish at 50%. (this is from 75 when it doesn't charge full for optimization; last night it charged to 100 so i will see how long it lasts me today.)
but my series 5 was awful, i did the update while on the charger, took it off at 100, went to sleep with it, woke up at 20%. and this is having theater mode on at night so always on display isn't on. something is goin on!