Receiving emails with “No Subject” in the subject after receiving the actual email

At first the No Subject duplicates (NSD) were from only one email address which is a Comcast email. Every one I received from this sender had a NSD.

 Now it is happening from a variety of email addresses and more frequently. 

It happens on xfinity.com website and on Xfiniy Connect app on iPad and iPhone and laptop.  Using any browser, mostly Chrome.  I do not use third party for email.   

Is is there a way to stop this other than creating a rule to have the NSD email sent to a folder?