> Pages forever load, when the issue does not happen in Chrome.

A bit tangential, but that's not a meaningful analysis (depending on how you tested):

            FF    CHR

  Site 1    n     Y
  Site 2    Y     n

Imagine a Firefox user: They try site 1, see Firefox fail, and so they try Chrome and it succeeds. Then they try site 2, see Firefox succeed, and stop there. They never see Chrome's problem.

It's like what I've seen some DuckDuckGo users say about search engines: 'Google is better because when I can't find something on DDG I do find it on Google'. (I think there's also some confirmation bias with Chrome and Google.)

It's like the old sales technique of comparing your product's features with the other product:

               MyProduct  YourProduct

  Feature A     X           X
  Feature B     X
  Feature C     X           X
  Feature D     X           X
  Feature E     X
  Feature F     X
  Feature G     X           X
  Feature H     X           X

It doesn't show:

  Feature I                 X
  Feature J                 X
  Feature K                 X
  Feature L                 X
  Feature M                 X
  Feature N                 X
  Feature O