monsters are spawning even if monsters are disabled in server

undrwater monsters are spawning underwater even if i set spawn monsters to false

What I expected to happen was...:
no monsters spawning

What actually happened was...:
underwater zombies are spawning under water and zombies and spiders are spawning out of monster spawners in dungeons

Steps to Reproduce:
1. set server.properties file
2. set spawn monsters to false in properties file
3. find dungeons with monster spawners or find underwater zombies in oceans