Tags disappear/scrambled after switching Workspaces

Is there an existing issue for this?

• I checked and did not find my issue in the already reported ones

Describe the bug

Tags disappear/scrambled after switching Workspaces.
The bug happens after switching between two different workspaces. Tags created in one database appear in the other, even if they don't share images. When switch back to the first database, the tag disappear, forcing you to reload import the tagged photos, which then appear correctly. But when you switch between databases using the preference in DT, the tags are lost (see steps).

Steps to reproduce

1. Two Workspaces (A & B)
2. DT set to create XMP files > after edit
3. In Workspace A, Imported Images (with existing XML sidecar files)
4. Created Tags for 100s of images in A (hierarchical)
5. Switched to Workspace B (which does not contain any images from A)
6. Tags created in previous A session appear listed in the Tagging window
7. Switch Back to A workspace
8. All Workspace A’s tags created in step 4 are missing from Tagging Window
9. Looking at file's Image Information, Tags are missing
10. Tags created earlier for pictures in Workspace B randomly attached to the wrong images in Workspace A.
11. (Still in workspace A) Remove all images and > add them back to library
12. All the correct tags assigned in step 4 tags reappear.
13. Switch back to B, A's tags still there
14. Switch back to A > Step 8 ....and so on, ad infinitum

Expected behavior

DT keeps separate tags lists for each database, and correctly assigns tags.

Logfile | Screenshot | Screencast

No response

Commit

No response

Where did you obtain darktable from?

darktable.org / GitHub release

darktable version

5.4.0

What OS are you using?

Mac

What is the version of your OS?

26.2

Describe your system

M1 Studio Max

Are you using OpenCL GPU in darktable?

No

If yes, what is the GPU card and driver?

No response

Please provide additional context if applicable. You can attach files too, but might need to rename to .txt or .zip

No response

No source file, test, or entry point is identified in the report. First reproduce the problem in darktable 5.4.0 with two workspaces and observe tag state while switching and reloading images. Done means each workspace retains its own tags and assigns them to the correct images after repeated switches.