So testing with actual users tends to highlight a few issues and this is no exception...
- replying to a topic that has an attribute using Quick Reply removes the attribute.
- editing an opening post that has an attribute using the Quick Edit extension removes the attribute.
- replying to a topic that has an attribute using the full editor removes the attribute, unless you have QTE moderative permissions set to yes.
- moving a topic with an attribute to a different forum keeps the attribute visible, even if the target forum does not have group forum permissions to use that attribute.