Mob Spawns are unreliable

Mob spawns are extremely unreliable with the beta software for Bedrock Dedicated Servers. When I am alone on my server I can see up to 16 mobs at the same time, it even almost gets annoying how many spawn because I run into them when traveling with riptide. However, when more than 2 people are on the server at the same time, almost NO passive mobs spawn whatsoever, and hostile mobs become harder and harder to find. The most obvious thing this affects is squid, guardians, and tropical fish. I have created a guardian farm on my server that spawns a significant amount of guardians when I am alone, but again, when more than 2 people join the farm just stops. Nothing spawns. I have the simulation distance set to 12 if this makes a difference. Also the farm design I am using for guardians is Silent Whisperer's design for the over world, without nether portals, if that also makes a difference.