I don't know what I'm doing wrong, this always worked in 16.5. I've made a set of grooms, merged them, added the deform guides and the sim guides, everything seems fine. But when I pipe the groom data into a Generate Hair node it just fails, saying there is no ‘skinprim’ attribute, but….there is. All the grooms going into the node have the attribute. The error says to use a “Guide Skin Attrib Lookup SOP” which I added to the hair gen node with absolutely no effect.
Oddly, it looks like I can connect the hair gen to the guide or guide deform directly without problem, but anything past a ‘groom merge’ is just broken.