Hi.
I'm ussing Archicad 14 (EDU) with all updates.
And i still having (i really don't know why, just happend) an issue with a lot of objects from the library... i can't change they materials, also appears with only one material, even if i change the object parameter.
One of the forum moderators. Versions 6.5 to 27 i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10 Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11
I'm experience the same problem and I suspect the graphic-card which, in my case, is GeForce GTX 550 Ti. I recently upgraded 4 computer's and they all have the same problem (and the same graphic-card type).
It's only in OpenGL mode that this occurs. Renderings are fine and Internal mode works fine.
I'll run some test and maybe I'll be able to post a solution soon.