When in the Mesh Preview, if you join a space and begin collaborating, open your menu and click on video record. It will work for a short minute sometimes but always crashes Mesh and then puts my HoloLens 2 in an unusable state where I cannot open the menu or access anything. I have to put the device into standby and bring it back up in order to regain access to the main menu.
Once that happens, I can click the 'X' for Mesh to close it. Then relaunch and Mesh will work fine.
This also happens when trying to open the camera to take a photo.