Question Duplicate Asseet Isolation Groups - Update Previuos Build error...

Can someone help me diagnose this problem? Ever since I started to run the Addressables Analysis rule to find duplicate assets and then fix what it finds, I'm starting to get this build error on occasion - not every time - when I go to "Update a previous build" :

Build Task BuildLayoutGenerationTask failed with exception:
Could not find file '/[path to project library...]/Library/com.unity.addressables/aa/iOS/iOS/duplicateassetisolation3_assets_all_85df873b6eb9beafda0868aad7575ab1.bundle

First, every time I run the analysis to find new dependencies and then fix them, a new Duplicate Asset Isolation Group is created. I have 3 of them by now, and in the Groups window is a group titled, "Duplicate Asset Isolation3"

Why is this error happening intermittently, not on every "Update a previous build" I perform, and how can I rectify it without having to create an entirely New default build? (thus forcing me to update my app - not good!)

Is it because I have modified an asset that is in the isolation group? (and the group has a local build path?)

I'm using Unity 2021.3.16f1

Thanks for your help!