Render In Place has become quite severely affected when Steinberg implemented the new video features (which is very much appreciated, btw). This is regardless of whether you even have a video track in your project or not. My problems are if there are more than 100 tracks, each render get slower and slower until it is absolutely crawling. Even when all plugins in the project are disabled (not just deactivated) I’ve already made a thread about this and it seems no one else has this problem, and none of the devs have replied.
Also, your problem could be due to an authorization glitch, like iLok. See if you have the latest iLok version update, and that you have activated your Syncron licenses?