Yeah maybe not every model is supported by Afterburner regarding the temp limit / fan curves, would be worth raising a case with them if it's not available in Precision or Afterburner Beta either.
Well funnily enough it has been good for over a month now, but I updated by graphics driver recently and it started again yesterday, so maybe it's related to that?
I'm thinking a fail-safe procedure is something like this:
When a new game driver comes out, DDU should be used in Safe mode to uninstall the current one completely
Then Geforce Experience can be reinstalled, and the new driver along with it.
Also make sure to keep Afterburner & RTSS up to date as there may be something going on there if the Temp Limit isn't kicking in (The Fan curve I never need to reset though, it always seems to work after a restart)
In Afterburner, the usual "Set Temp limit lower, apply, then to the max and apply again" should be done so it "sticks".
At least I've kind of got a process that keeps the game stable, but otherwise I'm directing EA back to this discussion. Even though it's "solved" it's not really, and our comments have been a great overview of the troubleshooting we're doing on our side. Again this only happens with Apex!