ports-mgmt/portshaker fails with "unknown command '--'"

[Serpent7776]

Hello,

since last update of ports-mgmt/portshaker I got

/usr/local/etc/portshaker.d/freebsd: unknown command '--'
usage: /usr/local/etc/portshaker.d/freebsd (update|clone_to|copy_to|merge_to)
[Error 23:49:11] Failed to update the 'freebsd' ports tree.

#!/bin/sh
. /usr/local/share/portshaker/portshaker.subr
method="portsnap"
run_portshaker_command $*

If I place `shift` just before sourcing portshaker.subr portshaker works as
expected. Is this is a bug of portshaker or there's something wrong with my
configuration?
Before update everything was working fine.

Thanks

-- 
/*
 * Serpent7776
 */