When someone comments on my YouTube videos, why does my email date them for 12/31/1969 at 7:00 PM?

I have my YouTube set up so that every time someone comments on my videos, I will receive an email. My email inbox on the computer will show that I have an email and my phone will alert me, but there is never anything there. I recently scrolled all the way to the bottom of my emails and found that all my YouTube comments were at the bottom and unread. They were all dated for 12/31/1969 at 7:00PM. Only the YouTube comments that people leave me are dated like this, all the other YouTube emails are dated correctly and appear at the top of my email.

Does anyone know why this is happening? My guess is that something is wrong with the settings, but I am not sure if it is YouTube, Yahoo or my phone.