Log in as a user
Create a new bookmark of an external work using a synonym of a canonical tag in at least one field
Wait a few minutes and confirm it shows up on the bookmark listings for the canonical tag
Log in as admin
Go to the tag listings, follow the link to the external work, and click on Edit External Work
Click the "x" on the tag you added to remove it, fill in the field with a new syn of a different canonical tag, and save the changes
Wait a few minutes
The bookmark is removed from the bookmark listing for the old tag's canonical. It is not on the page for the new tag's canonical.
What should happen:
The bookmark should be in the new tag's listings.
This has to be done with syns – it works fine if using canonicals. ticking instant's comment describes the issue in detail.