Hi Roger, I checked and it was doing this when also running continually. For some weird reason, the prop seemed to stop or it was a visual effect and also clicked then. I have it set at lowest and about 60% for high. But to answer your question, it as doing this while running.
I have it out right now and giving it vinegar, prop and everything seems to be fine, but have noticed that top "bearing in motor block seems like it is needing replacement. Rubber o-ring is also somewhat stretched out.