My session kicked me out while riding

I was riding up the Epic KOM in Watopia when suddenly, without my intervention, my session went immediately to the screen that says session ended, did I want to save it and exit. I saved it and exited, and it saved what I had already done, but lost the rest of my ride to the top. What happened?

Sounds like you have been Zwifted. Sorry about your loss. It can be very frustrating.