Emails with plus (+) symbols saving in CRM but not sending autoresponse

I've noticed that forms filled out with email address that have a + symbol in them are not receiving the autoresponse email, the data is entered correctly into the CRM but there is no email. Remove the + and there are no problems.

eg.

fake+hello@gmail.com - does not receive email (checked spam and filter etc) and there is no bounce back error or failure to send to the send email address.

fake@gmail.com - as normal, sends no problems.