I can't think of a reason for this behavior to affect multiple layers and be sensitive both to increases and decreases in the red color. I tried several different ideas but was not able to reproduce this, so I'm thinking Photoshop just got confused somewhere along the line.
The first thing, then, would be to Save As, then quit Photoshop completely. Reopen the document in a fresh instance of Photoshop and see if the problem is still there.
If the problem is persisting, restart your OS.
If that doesn't clear it, again quit Photoshop and this time, when you reopen the program hold down Ctl, Alt and Shift (Cmd, Option and Shift) while it is loading. Answer "yes" to the question about deleting preferences. Now reopen the document.
If that still hasn't got rid of the problem, expand the question with screenshots of your Layers panel showing all the layers.