Why would 'bleed trip' not resettable require a descent to 10,000, or cause a depressurisation. I understand what you said about a 2nd trip, but that would require a multiple failure. Is that what happened here? Bleed trip = 1 pack in high flow. It does not require a descent Fl250. That's crew discretion. If in a descent with EAI on it would be prudent to descend with more than idle to avoid a possible 2nd trip, of the operating bleed. However, previous posts suggest this was not the case, as the descent was made well before normal TOD.
Once again we are speculating in the dark searching for the needle of truth. It's out there somewhere, but often it takes a long time to reach here.