Confirmed, thanks for the exact repro here!
This reproduces exactly in Chrome latest as well with 1070x548
@david / @awesomerobot any ideas here, this is a real odd one.
I confirm this is not overflow-anchor I am seeing docked class on topic-progress-wrapper got in and out of effect.
My guess is:
- We add the docked class
- Page moves a bit
- Which makes us remove the docked class
- Page moves a bit
- And so on…