that trigger is not where the problem is happeing from, it is not happening in the second update, the problem is happening in the first update.
just fyi, the second update should only occur if "click here to send yourself a new email" link is clicked.
the section of code i highlighted previously is where the problem is happening:
$WA_AB_Split . "".(($row_SecurityAssistusers['UserEmail'] != $_POST["User_Update_group_Email"])? '0': $row_SecurityAssistusers['emailVerified']) ."";
This is checking to see if the email sent in the post is equal to the email in the recordset. if they are deferent, it sets the verified column to 0.
the problem is that the recordset name on your page is name "SecurityAssisttblusers", but that code is referencing a recordset named SecurityAssistusers.
i updated that section of code to use the correct recordset name:
$WA_AB_Split . "".(($row_SecurityAssisttblusers['UserEmail'] != $_POST["User_Update_group_Email"])? '0': $row_SecurityAssisttblusers['emailVerified']) ."";
the trigger for the second update behavior should be changed back to the original, as that behavior is not the cause of the problem.