Blank lines left in recipients user field in Voicemail Notification are not ignored

In the commercial voicemail notification module, blank lines left in the GUI in the recipients field are interpreted as null phone numbers and are assigned a priority of zero automatically. Calls are then attempted to the non phone numbers:

pbx_spool.c: – Attempting call on Local/@vmnotify-main for application AGI(vmnotify-main.php) (Retry 1)
chan_local.c: No such extension/context @vmnotify-main while calling Local channel

Not a huge deal except the zero priority means these calls are attempted before legit calls assigned a priority of one, and the timout must be exhausted between each attempt resulting in delays.