The server behavior was supposed to create a hidden form element in your repeated region to keep track of which record to update. It appears that wasn't created. It might have something to do with the original problem while inserting the behavior since it only creates it the first time.
It is probably easiest to correct the problem manually at this point. Just add this somewhere inside your repeated content:
<input type="hidden" size="1em" name="WADA_RepeatID_id_<?php echo $RepeatSelectionCounter_1; ?>" value="<?php echo($row_WADAtbl_master['id']); ?>">