All textures flickering black

Less than a week ago I was using Hammer++, nothing was wrong then I opened it last night and my textures started to flicker. It only does this in the 3D Textured & 3D Shaded Texture previews, the textures are fine in the Lighting preview.

I've checked that the textures are all LightmappedGeneric and updated the tool to the most recent version.

https://preview.redd.it/pr7iags6zuye1.png?width=1210&format=png&auto=webp&s=3c963af9873cad3d90523252a82594420c567191