Email content does not match email sender

Occasionally I will get an email where the content is switched with a different email sender. For example, I'd have an email from PCMag.com but when I preview or open the email, the content is from, say, Kroger.com. And the content of the Kroger email is the content from PCMag. Doesn't happen every time with a given email sender, nor does it happen everyday and always seems to be 2 emails delivered the same day...just odd. One possibility is that I use Manyme.com to create aliases rather than use my actual email address for my non-important email traffic.