trap_exists and cowboy ws

All,
I'm experiencing a situation where a process spawned after a cowboy
websocket handler upgrade request in init/2 has the process flag trap_exit
set to true, without me doing anything to set it.

This happens in Elixir, not sure if this is related.

def websocket_init(_state) do
    Logger.info("was trapping? #{Process.flag(:trap_exit, true)}")

=> this prints "was trapping? true"

Is this expected behaviour?

Thank you,
r.