File duplicity using script

I just ran into this issue and I’m not sure how it happened. I’ll leave this here in case someone’s googling. The script created duplicated files with a number appended to them. So I had several files duplicated:

This caused the script to fail with:

Uncompressing libraries vs2015 from
  End-of-central-directory signature not found.  Either this file is not
  a zipfile, or it constitutes one disk of a multi-part archive.  In the
  latter case the central directory and zipfile comment will be found on
  the last disk(s) of this archive.
unzip:  cannot find zipfile directory in one of ../scripts/dev/ or
        ../scripts/dev/, and cannot find ../scripts/dev/, period.
Error on or near line 176; exiting with status 1

Deleting all repeated files solves the problem.