MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
I can confirm the issue. I'm also having the belt slip while tightening/tensioning even with the cover on. (I managed to whittle off the corners on both sides to make it pass the frame). I downloaded it yesterday, Nov 21, 2018.
Printed using atomic filament PETG, same as I used on the bear extruder upgrades