I think I found the issue. Going to leave it here for future reference or comment by the Epic team in case I’m doing something terribly dangerous.
In the plugin script in C++, there is a setting for the Synthesis Plugin that determines the “LoadingPhase” of the plugin. I believe this determines when in the order of events the plugin code is loaded. It was originally set to “Default” but I think the problem with this is that my game actor code had been loaded before the plugin gets a chance to load. So I was getting a NULL reference to the script because the plugin hadn’t been loaded yet.
By changing the LoadingPhase to “PreDefault” it should load the plugin before the blueprint actor game code is loaded, so now when it looks it finds the synthesis script.
“LoadingPhase” : “Default” -> “LoadingPhase” : “PreDefault”
If anyone knows why this is a terrible idea, let me know 