I noticed two odd things with my last game:
My empire started at the bottom corner of the map, and I could not scroll away from this corner by moving the mouse to the edge of the screen. If I clicked on the mini-map to move the main screen away from the corner, I could scroll as normal, but each time I started the turn in the bottom corner, I could not scroll.

Also, after upgrading my starbase with a defense module, my "Turn" button disappeared. This makes it hard to play the game. I have the savefile if you would like to see it; however when I reloaded the turn button came back.

I know this is not a lot of info, but I wasn't doing much at the time except clicking the turn button.

Edit: after playing the game for a few more turns, I think I noticed a pattern...It seems to be happening when ship combat occurs...like it gets locked into an unresolved loop at times when resolving a combat.