When a glider is getting pneumonia or other respiratory issue, clicking when breathing may be periodic at first, and progress to every breath. It's not normal, and different from the happy clicking they do that comes and goes...the key is it goes. If it doesn't stop, have it checked.

My concern with the pics is the nose is also wet. I'm sorry I haven't read the whole thread, but if the color is recent, stays there, the wetness could indicate sinus drainage (gliders noses don't stay wet like cats/dogs do). With the combination, if it were one of mine, I'd treat for the possibility of a sinus issue (and have the teeth checked, meaning anesthesia and checking EACH tooth for movement), if that's a recent thing.