preview nodes incorrect

Any time I change a texture asset the preview thumbnails act like I changed ALL texture assets to that one asset. For example in below image I just changed the MainTex3 asset and now unrelated nodes are showing that instead of the level_noise asset. Reopening ShaderForge or Unity does not fix the issue

I've had this problem for a few months and it makes previews useless. I'm on Unity 5.6.2p2 with latest ShaderForge v1.38