Sapphire running 8.21. Strange GPS and map issues on Hiking activity. Possibly caused when Hydration prompt pops up

I’ve had the compass pointing the wrong way issue before this firmware update. Feels like it’s got a bit better, but it happened on a 6 hour hike yesterday. Fixed with a reboot. 

I noticed a couple of other bugs.

Bug 1

I have GPS altitude as one of my data fields. I noticed about an hour in that it wasn’t showing any numbers, just - - -. I rebooted the watch and it seemed to sort the issue. I also noticed that the watch hadn’t stopped tracking at all. I then got a hydration alert, I recorded some water being drunk, then realised the GPS elevation had stopped showing again. I did another reboot, things we working again. The next time I got a hydration alert, I cancelled it, and this time around, no issues with GPS elevation. 

Bug 2

During the hike I picked a waypoint to navigate to. I’d added it earlier using Garmin Explore. At first it worked. Then I got the compass bug. I rebooted. Things were fine. Then I noticed the map was showing the trail I’d just walked, but it was showing my actual point on the map from about 30 minutes earlier with the trail line going back to that point. (I wish I’d photographed the screen, but I was heading up a mountain on the Isle of Skye in bad weather). It looked like the watch was tracking where I’d walked to, but also thought I’d stopped about 30 minutes earlier, and was showing a connecting line back to that point. I rebooted and that seemed to sort it for a while. Eventually I gave up trying to use the watch to keep me on track. On the way back to my start point I tried using ‘navigate to start point’. This seemed to work fine. 

I never rely solely on a watch for navigation. (Tend to have phone, paper map, compass). But, I purchased this watch mainly for hiking, and the navigate to waypoints should just work. I’m getting pretty annoyed every time I head out, to have to constantly reboot and check to see if the £800 watch I have is actually working. I’ve owned a Fenix 2 then 5 before and never had this amount of issues. 

Other tech notes. 

My watch was connected by BT to my iPhone. 
I also have an inreach connected.