A recent example from me -- one VPN client of mine suddenly refused to connect one day for no discernible reason when they made a configuration change to their cisco vpn "concentrator" without documenting it or announcing it. Cisco AnyConnect GUI clients were fine and some magic happened behind the scenes to push the configuration change and, in typical Cisco style, avoid saying what exactly it was.

I had some esoteric monitoring machine that couldn't run anyconnect (for reasons I forget but almost certainly relating to it not having a linux arm64 client at that time) and naturally couldn't connect randomly one day with openconnect (which previously had worked perfectly). I asked what the configuration change was to prevent me having to reverse-engineer it. The response was "if you want to use unsupported clients we cannot offer any assistance [...] we are currently operating two heads down and we simply do not have the resources [...]." It took me about four or five hours to work out what change they had made, change the (122 line long) configuration file for openconnect, and then, boom, everything good again. A friendly "Hey, sorry about that -- we just $FLICKED_THIS_SWITCH because $REASON" would have been massively helpful and arguably take less words than their original response. (Edit: For context, approximately 10-20k people use that specific VPN. And their team is such that losing two members of staff temporarily is a major inconvenience.)

I totally understand it from the other side. IT departments have everything from state-sponsored ransomware attacks to important people loudly going "why doesn't the printer work any more". It's a different set of skills to being a C-junkie, a programming wizard, or, in my case, a young academic with one big grant and three PhD students trying to both do work, publish work, and get money to do more work where "work" is poorly defined and highly flexible. Over time I've noticed universities get far more corporate and many academics absolutely hate this, of which I am one. The "we control the network, bug off" may be technically true but at times it does feel a bit like an imposition of some sort of academic freedom, to be honest. At the very least, it's a nice little "dog egg" to find added to the pile of administrative crap to do for that day.

What you’ve just described is most post secondary institutions, public utilities, government, etc.