OP clearly states
“Normally for ShooterGame this doesn’t seem to be an issue but I am writing a plugin that spawns an entity from the
PostMapLoad event and doing that in this situation completely breaks the remote clients’ replication, but works perfectly
otherwise.”
I’m noticing Epic devs are really trigger happy to close issues without even reading. OP did all the work for you, right down to the the problematic line of code. It’s easy to see why it breaks it.