It is subtle but noticeable at all times, specially when the character is free falling. Is that something fixable?
It seems these jitters were introduced by in Godot 3.2(.2?), as they weren't there with previous engine releases.
After some investigation, I found that turning of the camera's Smooth property addresses the issue. Everything else I tried failed for now. It feels like we're touching an edge case of the camera smoothing algorithm or way in which transforms update in Godot.
Issues like these can be introduced when a game engine gets a new release; that's why game studios often freeze their engine version when producing a game, using new engine features only with new projects.
Thanks for letting me know, I'll add a note in the first lesson.