There are others who reported the same issue.
Their solution is to skip the backup process during wallet creation and do it later once the wallet is created.

The only similar behavior I encountered in my test is if I selected another option like "Digital", then re-select "Printable Paper Backup".
After that, neither "Single-Sheet" nor "Fragmented" paper backup options are selected, using "Create Paper Backup" button does nothing as expected.
But I failed to reproduce the issue when 'Single-Sheet' is selected.