Sync Event Setup Fails When Using POST api/schedule

Thank you for your message and for checking.

Regarding your questions:

The sync group has already been created, and a lead display is correctly assigned.
The sync event is also scheduled to the sync group, not to individual displays.

However, the issue we are currently facing is the following:

When a sync event is created via the CMS UI, it is displayed and works correctly

When the same type of sync event is created via the API, it does not appear in the CMS

Based on this behavior, the sync group and lead display configuration itself seems to be correct.
We suspect the issue may be related to the API-based event creation process or specific parameters required when creating the event via the API.

Additionally, I am not sure if this is the appropriate place to ask, but we are also facing another issue related to synchronization.

When playback is synchronized, only the lead display experiences a delay.
More specifically:

The delay occurs only during the first loop of the playlist on the lead display

From the second loop onward, all displays play back in sync correctly

We are currently looking for a solution to this behavior as well.
If this is a known issue, or if there are recommended settings or points to verify, we would appreciate your guidance.

Thank you in advance for your support.

Best regards