Seems consistent. When I play an automatic battle and try to watch it, it goes automatically but then switches to manual. Just try attacking the closest enemy like this, using the last army I have there (Barlog and Glade Runner).
#Bug report + repro save. [Watching auto battle switches to manual]
torn plover
I said it is consistent, but I ment it is consistent just for this save and conditions I mentioned. Happens each time I reload the save.