It says I have new email but I don't. When I did have new email, it didn't show me having any. TER coders, flip the bit, it's inverted

If you do not have new mail, it shows that you do and vice versa.  I figured that out earlier today when I got an email that I had new mail and it did now show the "new email" message.  But. When I went into my inbox, it was there.

Now that I read the email, and there is no new mail, it shows that I have new mail.

I am sure its just a minor glitch.