JL,
I suggest trying Safari instead of Firefox as a test. [you might need to designate Safari as your default browser, IDK how Citrix interacts w/ the OS, haven't used it at all for many years, or maybe you'll need to setup Citrix to use Firefox instead of Safari]
In the last few years, the rare times something on the web has not worked properly w/ Firefox, it has always worked w/ Safari. FWIW, I've been using FF as my main browser for quite a few years now, w/ Safari as my backup browser more recently, although I used to use Camino 'off the bench' as needed.
If it works OK w/ Safari, then you have at least found a work-around to your problem; if it still fails w/ Safari, perhaps you will learn something that will point you to a solution.
Kb