You need to restart the processes, so the injected agent for the deep application insights is removed.
Patrick is right. It is not necessary to restart the whole host, just the processes for which you do not wish to monitor anymore. Restarting the whole host would have the same effect but is not completely necessary.
Actually not even process restart is necessary here. The agents inside the processes will go dormant if you disable monitoring of a host. If you re-enable it, agents that are still injected should also resume monitoring immediately without any restart.