I'm having this issue too. In all other aspects the game works fine but freezes every time I exit. I really like this game so I'm not too bothered but I do worry if there will any long term affects on my systems.

Three years after your initial post and I'm having the same problem. Oh, and really bad lag. By minimum/recommended standards, my computer should be able to run this while still running Photoshop in the background; it's not even running properly as the only active program.

I had the same problem as well, but I since noticed that GOG galaxy would hang as well on exit every time the game crashed on exit.
So I started the game from the executable in its folder, and up until now, no on-exit crashes from the game; however, GOG galaxy still does, but only for this game.

I had a similar problem with another game (I think it was Mary Skelter), where launching from galaxy would cause a crash on start, while launching it from its folder wouldn't.
It's looking like galaxy's launchers have some weird issue with going in and out of games.