I don't know the changelog for 1.19e (it's not posted yet) but I had this problem in 1.19d and 1.19e too:
After playing for 30 or so turns when I click on "End Turn" nothing happens. It's not a crash to desktop or anything (I can still do everything in the game) but "End Turn" has no effect so I'm effectively stuck. I did do Alt+Tab a couple of times during the game but I am not sure if that's what triggered it or not.
Has anyone seen this problem?