Does a Cleanup occur and finalize pending items while a card effect (like Hidden Blade) is still resolving, specifically when Immortal Phoenix triggers after a unit dies mid-resolution?

Ruling: Cleanups should not occur mid-resolution of a card effect. Effects that are currently resolving should continue resolving before proceeding with cleanup steps.

Nuances:

• The rules currently don't explicitly state that cleanups can't happen mid-resolution, creating ambiguity
• This is similar to a previous question about Tideturner
• Rule 351.3 suggests that if another card effect or ability is currently resolving, it should continue resolving before proceeding with further steps