thanks for your ideas, but I've just updated to Cakewalk v2022.02, Build 029, and still suffering.
I'll raise a bug report with Bandlab, with the following "Steps To Reproduce..."
1. Open Cakewalk
2. New "Basic" project
3. Open PRV for the MIDI track
4. Add an Articulation (I used Chord Triads, and added a C Major Root chord)
5. Delete the Articulation
6. Open "Edit Articulation Maps"
7. Delete "Chord Triads" from the "Articulation Maps In Project" box using the dustbin icon, and hit OK
8. Reopen the Art Map Editor, and "Chord Triads" re-appears in the project.