It is in fact the same on a fresh boot. So the unplugged toggle-off failsafe part is failing
ETA: to clarify, I'm 90% sure it's letting me toggle back and forth between usbms and usbnet multiple times while plugged in. The issue that crashed it was testing whether it'd successfully yell at me for trying to do so unplugged.
Update: Yep. usbms-usbnet-usbms-usbnet-usbms-usbnet-usbms all worked fine (tested with file transfers) so long as I leave it plugged in
