I dont know if this hep but i had a similar problem if there is multiple e-mails from the same website in result in the box.
The problem is that you test the regex with only 1 mail in the box, after a run with multiple tread you can have multiple email for the same result.
The test of the regex work fine but multiple e-mails is not good for the same answer.
(she pickup only the last email or bug on the same)
I hat to found a regex for only 1 mail in result.
This is my solution:
(?<=[\w\W]*){-Variable.RandomEmail-}[\w\W]*{-Variable.MailDomain-}(?=[\w\W]*)
that work fin now with the 4.0.7.0
i had to found other temp solution to validate the mail before the 4.0.7.0
i have found:
http://www.sliqsubmitter.com/email-link-clicker.php its free but you can not schedule and only 1 mail box
the other SenukeX Mail Verification link, just say WOW she click on more than 1000 email in just 30 sec but you can not schedule and only 1 mailbox/ window