Possibly not a bug, but when a tag is renamed or when a tag hierarchy is changed, no changes are written to the images, despite Digikam showing these changes in the interface.

Clicking on "Item -> Write metadata to selected images" is required to actually save those changes.

Maybe a duplicate of bug #200162 ?

If this is on purpose, there should be some warning that this information must be manually synchronized with the database. If it is not, this is inconsistent with other metadata edits, which are written immediately to the file.

A possible alternative would be warning the user of how many pictures will be affected by this change (e.g. "Renaming this Tag will change metadata in 1234 files, is that ok?").

Either way, I feel the user should be warned, as it can lead to inconsistencies in the tag structure.