Hi, I'm relatively new to Substance so I'm not sure if this is a bug or if I'm just missing something.
I seem to keep losing access to material channel inputs under Properties-paint. What I'm talking about normally looks like this:

I'm using the normal channel to hold a Hard Surface normal so that I can stamp it on my model, but it's happened a few times now that I'll come back to the channel inputs and find that I can't see the contents of any channel, like this:

When this happens the only way I seem to be able to get access to the channels again (beyond just turning them on and off) is by restarting the application. Creating a new paint layer doesn't give me access, nor does looking at other existing layers.
I briefly checked online to see if anyone else was having similar issues but I probably don't know what to search for because nothing came up.
Edit: creating a new project gives access to the channels again, and I assume opening a saved project does as well; but I still can't find a way to get access to the channels without having to change projects or restart the program.