I've had the ACRO mounted to a Gen5 G17 MOS for north of 12,000 rounds with no problems. I don't see too many ACROs in the wild, but the ones I've seen aren't flying off of pistols.
There are a lot of variables involved in red dots and anyone running around making broad pronouncements about a particular optic based on seeing one specimen do something is rather absurd. It's one thing if it is your personal gun and you followed all the right steps to get it on the gun, but on a student gun?
That's a bit much.