Is Private Internet Access injecting their own Google cert?

I noticed something really strange happen today. I'm getting an invalid certificate warning ("This certificate is not valid (host name mismatch") while sending email through Google's smtp server. I decided to disconnect from PIA and send the email and, low and behold, no certificate warning. I reconnected to PIA, tried to send a test email, and got the warning again.

Anyone else notice this? I've noticed this happen several times in the past, but I didn't pay much attention to it. The cert in question is for mx.google.com