Auto/manual pause function disappeared mid ride

During a very long ride, I noticed that the function to auto/manually pause (bottom left button in the data screen) disappeared on my K2. The only thing I could do was switch between the data pages and stop the ride. Auto pause was on, and it was OK for a couple of hours, but that also stopped. 

Please note: 
- The ride took 26 hours
- I encountered heavy rain which messed with the screen obviously, causing several pauses accidentally 
- I charged the device 2 times from a battery pack, once for an hour, once back to a full charge, about 4 hours. All this while recording and riding.
- I was following a 600 km GPX file that was in 1 piece, non split.
- I was not using any other functions of the K2, and I did not have any sensors connected