I have noticed this weird anomaly with a Pipeline, when following along at home (karaoke mode I think you call it). When I hit a stage with a sh step, the step is rendered as if it is "open" (arrow pointing down), but there is no console output being emitted. The UI seems to be stuck there, and won't continue to the next stage's steps.

Interestingly enough, clicking the step "closed" and then "re-opening" it, seems to unfreeze the interface