I have gsx and level 2 and this problem began with the last update
If with "last update", you mean the PBR update, that doesn't mean the problem is *caused* by GSX. Just that, because GSX now uses PBR in P3D 4.4+, it requires the sim to have PBR support properly installed.
If you haven't updated the sim in the correct way to 4.5, which means updating BOTH the Client and the Content, every product that use PBR *will* have issues like missing or black textures.
I just got an email from a customer which had exactly the same problem as you, and he said he fixed by reinstalling P3D entirely.