Also, having this issue in Rhino 7. At first I thought it was a worksession problem (which has been an issue in the past), but the same thing happens in a singular model. It is not consistently white materials though, some do show, either correct colour, transparency, or bump mapping, but most of the material shows as white. I don't have time to troubleshoot or submit a comprehensive error report right now so reverting back to an older version for my deadline.
Enscape version: 3.3.0+74199
Rhino 7 SR16 2022-3-8 (Rhino 7, 7.16.22067.13001)
Windows 10.0.19043 SR0.0 or greater
(Physical RAM: 80Gb)
Primary display and OpenGL: NVIDIA Quadro RTX 5000 (NVidia) Memory: 15GB, Driver date: 5-6-2021 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 462.59