Hello, I am not sure if this is an ESRI problem, but I thought I would start here. I am currently running ArcGIS Desktop 10.6.1. My problem arises when a coworker opens up the .pdf document. When they open up the .pdf document and click on any symbology or text a hyperlink of sorts pops up as an untitled email with the address field that looks like this..

The strange part is this does not occur when I open up the .pdf document. Has anyone come across this issue?
Thanks