Okay, back at laptop and have had the chance to review my above post. Firstly, my bad, by "duplicated (linked)" I meant "Paste (reference)"
So, to explain a bit more fully. What
might fix this issue is ensuring all your identical browser sources are references of a single browser source, not just simple duplicates or set up from scratch each time. My thinking here is, while you've told OBS you don't want to refresh on reload, a browser source sitting in a dormant scene might be suspended for memory's sake, either by OBS, the website, or the underlying browser. Again, this is a guess, but one I think worth hearing out.
So, step one, remove all your browser sources – let's start fresh.
Two: Create your new chatroom browser source. Set it up how you'd like it to be.
Three: right click on that browser source and select "copy"
Four: Go to your second scene, right click in the sources area and select "Paste (reference)"
That should be it. Please let me know your results as I'd love confirmation that this fixed it, or feedback that it didn't.
I have the chatroom setup in two different Scenes, and then I add those scenes to one Source. I don't understand why this would make a difference?
Set up in two scenes then added to one source?