MC Version: 1.16.5
C&B Version: chiselsandbits-1.0.12-RELEASE-universal.jar
Do You have Optifine: No

Unless "Single Use Pattern" (wiki) is not the same as "Simple Pattern" (in game) - but both are created with paper and a quill - I'm able to reuse it multiple times. (I quite like this but I don't think it's intended.):

It is indeed not intended, and likely slipped in as a bug later.
Will patch thanks for the report.

Fixed in the new release.