in the update behavior, the ID value is coming from the WADAUpdateRecordID form element, this form element:
<input type="hidden" name="WADAUpdateRecordID" id="WADAUpdateRecordID" value="<?php echo((isset($_GET["invalid"])?ValidatedField("slideshowctaupdate","WADAUpdateRecordID"):$_GET["SlideshowCTAID"])); ?>" />
is set to use a variable that does not exist, SlideshowCTAID. chamnge it to use the ID variable:
<input type="hidden" name="WADAUpdateRecordID" id="WADAUpdateRecordID" value="<?php echo((isset($_GET["invalid"])?ValidatedField("slideshowctaupdate","WADAUpdateRecordID"):$_GET["ID"])); ?>" />