I have recently had similar issues and discovered that the replication calls from custom events are only performed if the replication setting of the BP under class defaults is set to ‘Replicates’.
In our project, the player controller is not set to replicate, so I’m going to take a stab in the dark that yours isn’t either. Our solution was to call functions from other BP’s that did replicate, only because we don’t know what problems we might cause by enabling replication on the player controller with a week to go before release.