After having those DX11 Crashes for the first time i got a possible solution from a FC Member (Thanks to Iris Zolwe).

Clearing your downloadcache seems to fix the issue, didnt have a Crash since i did that.

Go to Steam->Settings->Dowloads->Clear Download Cache.

WARNING: After doing this Steam logs you out wants you to log in so have your accountname and password at the ready.

Please respond to this thread if it did help you so we can see if this might be a wider spread (Steam) issue.