Quick patch by plugin author:
in the peters-collaboration-e-mails folder located in the plugins directory,
Open up: peters_collaboration_emails.php
Find: get_edit_post_link( $pce_object->ID, false )
Replace with: preg_replace( '(https?://)', '', get_edit_post_link( $pce_object->ID, false ) )
There are multiple instances of this code (about 3), so replace all of them and it should work, the plugin hasn't been updated since last year so this is just a quick patch, hopefully the plugin author will get around to making an update.
Thank you so much for the assistance! It is always great to hear from someone in the community.