The Flexible event-level configurations explainer says:

The use of priority in the trigger attribution algorithm in the case of multiple attributable triggers remains unchanged.

But that proposal indicates that a single report can be derived from multiple triggers, each of which can have a distinct priority, so something about the use of priority must necessarily change in order to implement the proposal. At least, there must be a way to compare two reports, at least one of which may have been derived from more than one trigger.

Additionally, it is unclear whether the scope of prioritization is within a reporting window (as it is today) or within a <reporting window, trigger data> pair.