Hi,
Mauro is right, we solve this issue gracefully for event QR codes in our upcoming April release, but for now, you can use the code below to render the right event registration ID (enter the event GUID please):
<!-- {{#each contact.msevtmgt_eventregistration_contact_msevtmgt_contactid }} -->
<!-- {{#if (eq this.msevtmgt_eventid '<please insert event GUID here>')}} -->
<p> {{this.msevtmgt_name}} </p>
<!-- {{/if}} -->
<!-- {{/each}} -->
What I am doing is:
1. Looping through all the event registrations for this contact and selecting the right registration, based on the event GUID
2. Adding the event registration ID field from the picked up registration ID record.
I hope this helps in the intermediate.
Thanks