Hi, same problem here, also on Firefox. I confirm the comment above, it seems the elements of the sections not in the current field of view are hidden. It's probably done on purpose for performance, but the behavior on Firefox resets the height of the viewport, hence the jump to the top of the page, which causes the first element to reload, and so on and on. Some examples :
On plan to watch, the currently watching and completed elements are hidden :
On dropped, same as above with the addition of plan to watch now out of view also hidden :