I have take a look on the single player and multi player.In single-player melons and other related things based on chunks are working more than 1 chunk.But here its acts like only one radius of chunks is active in updating(The block updating is something else)The problem with lowering the chunk updated radius that the mob handler is shutdown
Mob handler: (Tells the main file how many of every type are going spawn around you.Also handles which chunk is slime armed and not)
Yeah its prevent lagg.But also prevent mobs and animals its also stops Monsters to dispawn.
If its can be fix it many players will be happy also the mooshrooms are going spawn naturally
Thanks