What I found is that if the package you are loading does not exist, then prior to the merge Monticello creates the "new" package - presumably so it has something to compare against. ��(As an aside, if you do not proceed with the merge, then that "new" package remains, which is poor behaviour.) ��That works with a package without tags.�� With tags, I think it is noticing that the "new" package has no tags.�� So one solution might be to also add the tags when the "new" package it created pre-merge, but that seems a bit backward. Ideally the "new" package would never be registered in the system until the merge is actually executed.

I logged the following to deal with that issue as a dependency for the others.