This happens from time to time for us as well. One of my db admins has to go in and create a stub for the missing/un-editable registrants (ie. it shows 3 people in the group but you can't expand the group) and then we have to call them and add them back in manually. We never know what causes it, but it happens. Closest I can "guess" is it may be a javascript issue where the end user's browser has it turned off, or their browser is not happy with the jquery version DT uses. No clue... depending on the volume for the day, we have to do this usually at least once/twice a day when price changes are coming up (3000 member conference).
mindgame - It's really hard to say, but if you want to submit a ticket telling us example record IDs that have this issue, we can do some troubleshooting.
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