Yes, it's known bug.
Unfortunately rotation and scaling are done by two different libs, and their are slightly incompatible. Since lib for magnifying is not maintained at all and poorly written… well, maybe someday I'll find a time to rewrite it from scratch.
Also, wrong project. unshred is for python CV lib, you need to report this issue to unshred-tag
Yes, it's known bug. Unfortunately rotation and scaling are done by two different libs, and their are slightly incompatible. Since lib for magnifying is not maintained at all and poorly written… well, maybe someday I'll find a time to rewrite it from scratch.
Also, wrong project. unshred is for python CV lib, you need to report this issue to unshred-tag