"Confirm Event Invitation" message template has a bad variable

In the above-mentioned template, there are two URLs generated that are ostensibly the same:

{capture assign=selfService}{crmURL p='civicrm/event/selfsvcupdate' q="reset=1&pid=`$participantID`&{contact.checksum}" h=0 a=1 fe=1}{/capture}

and:

{capture assign=selfService}{crmURL p='civicrm/event/selfsvcupdate' q="reset=1&pid=`$participant.id`&{contact.checksum}"  h=0 a=1 fe=1}{/capture}

$participant.id is a valid token in this context. $participantID isn't. Easy fix.