Position in route update with Message API

Summary:

We are trying to update the position in route for a set of activities assigned to a specific resource on a specific date.

However, when our custom plugin sends an update (or close) message to the Oracle Field Service API and we modify the activityList with updated position_in_route values, the system unexpectedly sets the position_in_route to null. As a result, the activities keep their original order and nothing changes.

Is there a supported way to use an internal message or another method to correctly update and maintain the activity order within a route?

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