No Naturally Spawning Hostile Mobs

Running a server for me and a friend, upon updating from 19w02a to 19w03c, hostile mobs stopped spawning naturally. They spawn from spawners still and can be summoned but will not spawn in the dark. This persisted after updating to 19w04a as well. Settings have been checked that mob spawning is allowed and difficulty is set to normal. "--forceUpgrade" command has also been attempted after backing up the map in order to attempt to fix the issue to no avail. Most Recent Save Folder has been uploaded in parts. Even when Loading this in Single Player, no hostile mobs spawn.