Next Clip Shortcut Not Working

My next clip shortcut (pressing the ' key) is not working. It skips forward correctly one or two times, then stops functioning at all. I can skip back by pressing ; without problem, but the skip forward just dies after a couple of presses.
It's not my keyboard as it doesn't work on my bluetooth keyboard, wired keyboard and builtin laptop keyboard. The key is also mapped correctly in keyboard customisation.
Any one have this problem (or a solution?) it's hugely frustrating.

I find it working normally with the default shortcut in Studio 20b2 for Windows.

I am having a very similar issue. The next/previous clip shortcuts (up/down arrow) suddenly stopped working after using the beta for a week. It just skips a second or two.

HOWEVER,

It works in other timelines. I have no idea what I could have changed accidentally but it doesn't work in a couple different timelines, and it does work in others.

I am about to update to the 20beta3 to see if that helps. Otherwise I may have to accept making a new timeline and losing my markers.