Okay, if you start breaking a block and quickly switch to a sign without releasing the mouse, the crack will remain on the block you were originally breaking. It also works if you switch from the sign to a brick. After a few seconds, the crack will disappear.
Linked issues
duplicates 1
Attachments
Comments

Ugh... I thought I searched for it well :|

I adjusted the original issue with the infos from this issue. Thanks!
Duplicate of MC-62124