Plone 6: Cancel Adding page without title, not possible: A bug?

Somewhere from 6.0 to 6.0.5, Adding a new page can not be cancelled anymore, unless you add a title (or move the cursor to another field).

Is this a 'bug' in Plone, or is it 'something we have to live with due to bootstrap version / html5.

If not: Where should I report it CMFPlone / Barceloneta ?

If in doubt report at Issues · plone/Products.CMFPlone · GitHub