Upon further research and thought, this is what apparently happened: The missing calendar item apparently did not get saved, possibly due to my listing error or a system problem, likely my error, as sometimes I fail to note an error that prevents saving the listing. I must not have noticed that and somehow reused that useless listing by overwriting all the content, as I would do with any other "list similar", to list the next item in my workflow, which was the teacup. Then I had no calendar listing and a teacup listing. All is fine, except that somehow eBay still can tell somehow that the listing once was associated with a calendar, even though that word no longer shows up in any of the listing content. That's still the the strange part. Today I relisted from scratch which I hate) the missing calendar which should now be findable.
