A Basic multi-card note cannot be changed to a Cloze type

Anki Desktop
1

All target card slots map to Nothing with no choice possible. No Empty cards. How could that happen?

Anki 2.1.22, 2.1.26, 2.1.28.

2

Anki currently only supports mapping one of the templates to the cloze template. I believe there’s an add-on that extends this.

3

But that note can’t be mapped at all, not even a single card.

4

Works for me - if issues persist after ruling out add-ons, please provide a reproducible example.