Somehow I have managed to 'disable' some keyframes in an effect and they appear fainter than other keyframes. It's the 3rd & 5th keyframes in the screenshot.
They still act as keyframes in the shot, and I can select them and change their 'temporal interpolations'. I can cut them, paste them and move them but when I select the property and use previous/next keyframe it skips them and jumps to the next 'undisabled' keyframe.
It's happened to 2 effects on a text plane. In another composite shot, where I use the same effects, all keyframes are OK for previous/next selection.
I'm not sure when they changed or what I might have done to change them.
Is this a known phenomenon?