Emails from workflow have very long file names

Were having issues with not being able to open attachments from workflow emails because the file name is too long. The test file attached had this file name originally :  IP Ping Full - 6_26_15.pdf

this is what it looked like after being sent out from GP: IP Ping Full - 6_26_15.pdf-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Any idea on why this would happen?

Thanks for your help in advance