This is similar to what I have noticed although I am not saying that the issue has the same cause. I tried using my 1080Ti card to render and used the new render default for Superfly and it had Branched Path Tracing ticked. In the render the hair that drops down over the eyes of my figures interacts with the eyebrows and the eye lashes and renders as unsightly blobs. I tried it with the CPU, same result so I went back to my old Superfly defalt with Branched Path Tracing unselected and the problem disappeared using the CPU or the 1080. Using the default I was also able to get the same detail as before at least using the CPU, I did not try with the GPU as Poser still does not play well with a 1080, not with mine anyway, as slow as the CPU but nowhere near as stable.

 

 

I use Poser 13 on Windows 11 - For Scene set up I use a Geekcom A5 -  Ryzen 9 5900HX, with 64 gig ram and 3 TB  storage, mini PC with final rendering done on normal sized desktop using an AMD Ryzen Threadipper 1950X CPU, Corsair Hydro H100i CPU cooler, 3XS EVGA GTX 1080i SC with 11g Ram, 4 X 16gig Corsair DDR4 Ram and a Corsair RM 100 PSU .   The desktop is in a remote location with rendering done via Queue Manager which gives me a clearer desktop and quieter computer room.