Why they designed a cover that was so prone to falling off… as to warrant a sensor or whatever to detect it, instead of designing a cover that just doesn’t do that?
I was monitoring this print remotely (Bambu P1S), so I'm not sure what actually happened. It's possible that it failed for other reasons, and then the tool head got tangled in spaghetti and disassembled itself.
It's held in with two fairly strong magnets, I don't think it falls off on its own. If a print falls over and catches on the extruder it could push the front off. I've had it happen for that reason.
Personally..... I'd just have left it off if I was them. I can't imagine a little plastic shield helps hot end temps
depending on the design, it might be to control air flow around the hot end's cooler block.
it's usually best to have some type of duct go from the fan and around the back of the block rather than just being open air- it keeps the air contained until it does it's job. But again, the only Bambu I saw was at microcenter and I was in a bit of a hurry so I didn't get a good look at it.
I've printed on mine for nearly 1000hrs now, never had an issue with that or prints not sticking. Just have to prep it well and make sure there are no scraps under it.