I am running java 1.14 and the switch from 1.13 to 1.14 has caused guardians to stop spawning in the area where an ocean monument used to be that I cleared out for a farm. I cleared an ocean monument and halfway though making the farm update 1.14 released. After the update no guardians are spawning in the former ocean monument space and I have already put a considerable amount of work into the making of the farm and a civilization in the surrounding beaches with the prismarine/xp farm as the focus.