Hey hey,
I experience both and have comments for both issues:
Majority of active minutes are below zones -> This one I believe is expected. Since the update, you are now getting a personalised heart rate zones which are more precise (at least that's what Fitbit says of course 😊 ). With that, it is quite possible that your fat burn zone is now measured quite higher than it used to, hence - most of your walks would not ever hit the active zone mins.
I cannot say whether this is more accurate, but at least to me it seams plausible - before the update, I personally was quite often in Fat burn state, even when I was not doing any exercise whatsoever. So, all in all, I'd say the new personalised heart rate zones seem more true to real life.
Connected GPS not working -> I experienced this issue in the last few days as well. I even contacted Fitbit support about this. What I noticed - the issue started occurring once the new "Mindfulness" tile appeared in my Android app. While I was chatting with Support, I figured out I can test removing the tile from the app and try again. And what do you know - the GPS connected in a matter of seconds! Seems like this new tile is breaking the GPS connection somehow. I am going to create a new topic about this particular issue hoping it will gain traction and Fitbit will notice and provide a fix.
I hope this helps.
