I’ve been experiencing the problem on Firefox iOS for weeks as well. But I haven’t gathered any concrete information. For me, it doesn’t seem to always be a problem, and I seem to have a problem loading any page from the summary page (even attempting to visit sites unrelated to bunpro). But If I open up a new different tab and visit the dashboard or anything else in this state, they load immediately.
Essentially I can’t change the tab’s url to anything else after visiting the summary page. If I wait a long time, the return to dashboard button can work though.
Sorry I don’t have anything too helpful on it!