mac OS frequently dropping to 1 FPS

Since updating my Steam version of PoE running on mac OS Monterey on Aug 3 at 1:45pm EDT (Build ID 11796902), I have experienced new and absolutely horrid graphics performance.

Something big has changed in PoE. I no longer see any of the persistent shader corruption issues that plagued PoE on mac OS for months. Hurray for fixing that annoyance, but honestly the current build is unplayable.

Now, whenever the graphics load gets even moderately interesting, e.g. while fighting a typical sized group of monsters, the fps abruptly drops to 1 FPS (or lower). Once the fight is over, or if I am able to run away to a less busy spot on the map, FPS returns to my usual 30-ish FPS.

I have reproduced this with two different characters using very different skill gems.

I'm attaching one screenshot with the performance graphs to give an idea of how bad and how frequent the problem is.

To follow up on this, the system having dire graphic issues was an older Intel mac (the ol' coffee can). Before this patch, that system had little difficulty achieving 60 fps and it has 64GB of RAM so it's not running out of memory. Rendering there is now limited to about 30 fps.

I have an M1 iMac that is not having such severe issues, but it can only hit about 22 fps now, when it used to manage 30 fps (even with minimal graphics options enabled). However, once I started looking for it I noticed the same sort of issues as with the other system. The difference is that I think I'm seeing regular, but brief interruptions in rendering, roughly a quarter of a second long.