Hi Commun,
I created 3 event registration records for same contact and tested several times in preview mode.

It seems that sorting is random(no criteria) in each time.


Dynamic expression in marketing email is based on a javascript template library: Handlebarsjs.
In pure HTML page, we could do sorting on output of 'for-each loop' by creating our own sorting function(a feature in the library),
however, js will be blocked in HTML email by most email service providers due to security reason;
Thus we couldn't use any variable to store data in dynamic content, or do sorting on output,
in other word, there are limited expression options(may only examples in documentation) for us to add dynamic content in email content.
Please suggest your requirement in Ideas forum to make it could be available in future version.
Regards,
Clofly