I have just done the following: restarted Mac (didn’t help), in DT preferences changed “to searchable PDF” to “no action”, removed the checks for “Move to trash” and “Enter metadata after text recognition”, restarted DT, scanned a document, in DT preferences changed “no action” to “to searchable PDF”, checked “Move to trash” and “Enter metadata after text recognition”, restarted DT, scanned a document - now works as it should.
I have refrained from sending the Bug Report; but maybe this post will help anybody else who experiences the same problem. And if not: it was nice chatting to you all, thanks for your help!