Apple Watch: Training app stops recording GPS track after first interval in custom workout

I was doing a custom interval running workout today (warmup, 20x1 min fast/2min slow, cooldown) where warmup was open. Started the intervals at approximately 3km and when my run was finished, I see that only the GPS track until the first interval started was recorded. Overall distance, heart rate, etc. were all ok.

No issues with "open runs", I am running daily and all are recorded perfectly. Also did custom workouts in the past, no problems.

I have seen this being reported by other users in running forums too. Always related to custom workouts and always after the first interval starts.

Hard to say when this issue started, maybe November or so as the other posts suggest? WatchOS 11.1 related?

Apple Watch missing part of map Custom Ru… - Apple Community

Apple Watch losing map during custom work… - Apple Community

I am using an Apple Watch Ultra 2 with watchOS 11.2.