When set to confirm paste of 1 or more lines of text:
pasting "a" results in confirmation
pasting "a<crlf>" results in confirmation
pasting "a<crlf><crlf>" results in confirmation
and so on

When set to confirm paste of 2 or more lines of text:
pasting "a" results in NO confirmation
pasting "a<crlf>" results in NO confirmation
pasting "a<crlf><crlf>" results in confirmation

"a" is technically 0 lines of text - there is no <crlf> at all
even then, there is no possible option to turn off confirmation of "a", but keep confirmation of "a<crlf>". Increasing confirmation from 1 to 2 lines allows both "a" and "a<crlf>" to be pasted without confirmation.

The behaviour was correct in prior, 6.14 version.