I've had this issue off and on with my Fenix 7 for over two years now... most frustratingly when I need to have the map up for course routing.
The issue is the same for Road and Trail running, the map screen would automatically change to the first-most screen over and over, making glances at a map/course impossible, and frankly ruining many of my trail runs.
I thought that if it keeps changing to the first screen from the map, if I rearrange all the screens so the map is the first and default one it may still change screens on its own, but at least it would be to the (now) default map screen (at least for trail runs)..
Was this what happened? Nope!
Now my map view (which is the first and default view) will automatically change to the 3rd or 4th or 5th screen, inconsistently, still causing me to need to press a button multiple times to switch back to the map... now it's just the up button instead of the down button.
I have experimented with disabling the touchscreen except for the map view and turning off the touchscreen completely, neither making a difference in this behavior.
I regularly need to zoom into the map/course because the heading bug and course arrows can be too small to see and too far down on the screen and obstructed by the two data fields I display with the map.
I am also aware of the AutoScroll setting, and it is and has always been set to "Off"
On more than a few occasions, I have been in a dangerous situation because of this bug when I didn't have cell reception/signal or it was raining and unable to interact with my phone, and I was lost and reliant on the map being available on this watch...