I just had the same problem, reconnected everything. Play in Editor worked fine but Standalone spawned nothing. Restarted the engine and found all the links were broken again. Quick renaming of the struct fixed it.
Structs seem a bit unstable at times. I almost screwed up my project by messing around with some variables in a struct (that is a variable in a bigger struct). Fortunately managed to fix that and I’ve no doubt this disconnecting problem is to do with that. Gotta be careful around these things haha.
Thanks for posting your fix anyway! Worked like a charm.