Has POE1 engine been updated in the last few weeks?

I have close to 9k hours in POE1, all on a single machine running a GeForce RTX3080, an i9-11900F and 32gb of RAM. Main display is 4k, with two 2k displays.

Generally I have been getting 60fps from POE1, but in the last week or two things have started getting extremely choppy. 7-8fps in abyss or ritual, the two mechanics I am playing most at the moment.

I have played with everything. Graphics settings in-game, graphics settings from Nvidia, runtime options, malware scans, reinstall, move game to different storage. The only thing I have not yet done is reinstall Windows, and that is unlikely. I have not installed Windows 11 24H2.

So - having checked everything at my end the question becomes has GGG changed anything in its engine? For the moment I am going to install one or two of the games in my library in case POE remains unplayable, but this is not my preferred solution. Help me GGG, you're my only hope!