Well on closer inspection this morning, I noticed that the upper jockey wheel was contacting the teeth on the 34 cog and creating a bumpy motion, so either the chain is too short, or something else needs adjustment that I'm not aware of...?

Fiddling about with some other aspects than the limit screws increased the distance between the 2 gears enough to reduce the bumping noise. Hmmm... wait the bike is upside down right now, maybe gravity is playing into this, because I didn't notice is yesterday on the stand?