problem when switching

Have you checked on the status of things in the database directly, to see if things migrated properly on that level?

It has, just the edit terms page of the new taxonomy are not showing, although the count is right but the terms are not visible.

Unsure what’s going on with that, especially if the database is showing them all matched up like expected and appropriate. That feels like a WP Admin issue.

Ok, what can I do to fix or troubleshoot it?

They show up when I search in the terms page. So I’m just going to create new ones and transfer, delete the old ones.

Figured out why it did that. If moving a taxon that was once a child to a non-child taxon, it wasn’t showing in my terms list. As long as I searched, it would show so I just had to edit each one and save, now it shows up.

Thanks for the updates as you found them. The hierarchical detail can definitely play a part in things.