Okay, I am in two channels.

The marker just updated using the Ctrl+L input

The marker works as normal in both topics for a few posts then refuse to update from the position until I use ctrl+L again. I'm not sure if I can be more clear on my steps as there really are not any more.

It sometimes takes awhile for it to stop working, but it no longer updates it position after awhile even when it's no longer the active window. It just stays where it was.

It's hard to get an accurate reading on when it stops updating as it happens randomly but once it stops updating I have to reset it with ctrl+L to get it to work again.