This has been an issue for many years and is specific to people using Ubiquiti's security camera management platform and Firefox. As seen in these links
https://community.ui.com/questions/Protect-Live-View-slow-in-Firefox/ad0a744b-64e0-4b5d-b34e-fb0ebb8...
https://www.reddit.com/r/Ubiquiti/comments/vz86tm/psa_protect_is_awful_in_firefox_but_works_rather/
I think the issue stems from how Firefox is processing the video stream, and it'll usually "work", but if you try to seek through the timeline on any particular footage it can get hung up loading for long periods of time where Chrome and Chromium based browsers load in seconds or less.
