I've updated my 1030 twice in the past month to because I was having issues with uploading rides to the cloud. (the first update didn't help, second did).
The first update took the Heart Rate setting in my screens and changed it to something called POC. What is that and why would it do that? I had to go back and fix all my data screens.
The second update, which has some neat features, decided it would wipe out my custom max heart rate, which is in a very unintuitive place to begin with. My first clue was finishing a ride Monday and being told that I'd just hit a new high of 167, which I know isn't true. I then nearly passed out when it told me I needed to rest for FOUR DAYS after a moderate 40 minute ride in the woods. FOUR DAYS. I've gotten 42 hours before but never days.
I looked at my zone chart and found I'd spent 71% in zone 5 and that's when I realized my max heart rate had changed.
I must be the only one this has happened to as I see no mention of it here.
So Garmin, knock it off. These settings are a pain to setup to begin with, and then finding them again to fix what you've changed in an update is beyond annoying.