The interpreter used by this example script is installed at another location on Debian systems. Normally the path should be updated to match the Debian location.
Whilst the script may work, it is in violation of Debian Policy. This may have been caused by usrmerge.
Note that, as a particular exception, Debian Policy § 10.4 states that Perl scripts should use /usr/bin/perl directly and not /usr/bin/env, etc.