Session Time out for sure. One of my rec's was a tech guy, Masters in Compsci. I just double checked with him.
Sounds like your recommender attempted to type out everything in that two hours. For all of mine including Haas my rec probably spent less than 10 minutes total logged in - 1 minute to log in to download and copy and paste the questions, logoff, work offline for several weeks, login, copy paste answers back in. And in both instances the timer reset to 2 hours upon login.
To help with your R2 apps and this rec, I have noticed that most schools (all of mine at least) post their rec questions online somewhere on their official website, so recs can get a head start even before the official online forms were ready for entry.
eg.
Haas:
https://mba.haas.berkeley.edu/LORFall2011.pdf