Strongly agree that with certain teams you don't need a regular standup. That's part of why I think the decision to do a standup should be left to the team themselves, absent some clear dysfunction bad enough to require outside intervention. Otherwise you're probably just wasting everyone's time with 15+ minutes of boring crap that could just as well be a 2-minutes-to-write daily status update message or email to the project manager, assuming they can't get the status info they need out of Jira or git commits and skip the side-channel status updates altogether.
I guess another major tell aside from "multiple unrelated teams are in the same standup" might be whether, if every single non-manager/PM quickly checks in with the rest and they all conclude a formal standup's not needed that day (or the entire week, or whatever), a standup either still happens or else someone (a PM or a manager, probably) gets really bent out of shape if it doesn't. If so, you're likely dealing with a regular ol' daily status meeting. And again, that's what a majority of "standups" I've seen have actually been. They're not for the team, and however they manage to occasionally serve the team members' needs is accidental—they're just micromanagement and "agile" box-ticking.