Original thread: https://discussions.unity.com/t/behavior-event-channels-not-initialized-when-start-node-is-run-build-only/1556967

*Description*
Event Channel is null in build when called directly by OnStart node.

*Reproduction steps*
# Create a new Behavior Graph
# Create a new Event Channel
# Call {{SendEventMessage}} node using the EventChannel
# Bind the graph to a scene (using a BehaviorGraphAgent)
# Build the scene into a player

*Expected behaviour*
The EventChannel instance is always valid to be used.

*Actual behavior*
The EventChannel instance is null on player build.