While this issue has been discussed for pre releases like 1.14.1, while some report it not always happening in some of the 1.14.2 pre releases. The server has updated, pre generating a 1.1.4.2 from scratch. From the start excessive amounts of mobs have spawned, and at one point the server was as 0.92 TPS at one point. The hostile mobs where eradicated but that did not ease any spawning issues, even with rarer spawning mobs like ocelots making the game unplayable.