I can confirm this.
I also hope I'm doing this right.
I'm kinda new here.
I'm new here, but i can confirm this.
I have been messing around in superflat mode with the biomes set to deep ocean with ocean monuments spawned evereywhere, but guardians just won't spawn.
I have been trying to use ocean monuments for use in a survival map, but this kinda a big wrench in my plans.
Its still happening, should be unresolved.