I’ve had the same for around 2 months, you can get into a scenario where it starts working again but i didn’t figure it out. I’ll see if i can work it out tomorrow might be our setups.
For a temp workaround, you can use right-click -> “copy link address” on the 6 hour image and change the URL (TO and FROM vars) to use unixtimestamp. Then you can just change the port ID if your inspecting multiple ports at a particular time.