--deb-after-purge Does not Write to postrm File

It appears that the --deb-after-purge flag does not work in fpm version 1.9.3.

The following always works as expected by including the contents of remove-file within postrm's after_remove() method when creating a debian package:

fpm \
  ... \
  --after-remove remove-file \
  ...

The following does not work as expected:

fpm \
  ... \
  --deb-after-purge purge-file \
  ...

I would expect that the contents of purge-file would end up within postrm's after_purge() method when used.

Also, if one only provides the --deb-after-purge flag, the postrm file is not created and does not exist in the completed package.