The reality is they probably don't know the full scope or root cause and are going off of limited reporting coming from their beta channels.
But they likely determined the impact was low enough that they could still ship the update while they investigate further.
There are similar known issues reported in the update KBs all the time that sound much worse to me as an admin but are as equally low impact in the end. But they're not as easy for the layperson to latch onto like these low-effort "VPN no worky" articles.
Regardless, none of this absolves IT of the responsibility of testing patches.