The only serious tweaking I've done has been to disable cleartype and completely remove Segoe UI. Adobe Photoshop didn't react nicely to that; it is possible that there's something in conhost that's hardcoded to Segoe as well.

I'm not seeing this behavior on my desktop (everything pastes in cleanly) so I'm starting to dig in and figure out what the diffs are in my two setups. 

Is there a debug build of python for windows available or some other way to trace this crash?