This issue from the old tracker: https://feedback.bistudio.com/T196093
Was marked resolved back in 1.7 but is still happening for dedicated clients when the vehicle is server-spawned and not local. I cannot replicate in GM, single player or workbench at all, but can faithfully reproduce it on a dedicated server when the vehicle and it's crew are spawned by server code.
Reproduction steps:
1. Write a script that spawns a vehicle and crew + gives them a waypoint on a dedicated server
2. In GM drag a character in front of the vehicle so they honk their horn
The horn will latch on and never stop until that driver is dead or deleted. It seems as though CharacterInputContext.SetVehicleHorn(0) just isnt being replicated because even if I call that on the server with a 10 second timer it doesnt seem to stop the horn for a client