Wold Spawn Chunk not working as expected

Nothing inside spawn will grow, even if players are present inside spawn, also command blocks at spawn will affect areas outside of spawn as expected, but the same commands meant to work inside spawn, do not work. In past versions this problem did not exist in our world we had melons growing as a new player food source and had hostile mobs die via command block when they entered spawn.  Yes commands have been updated to current commands.  Anyway I kept a player at spawn for for 6 hours, real time or about 20 Minecraft days, there was absolutely no growth of the melons, none! Also the command block meant to kill hostile mobs at spawn does not do anything at all.   Mobs just come in and kill new players. Meanwhile another command block at spawn that refers to a village we wanted protected outside spawn  kills the mobs every time when that chunk is loaded. Additionally a kill command  issued from the console or the in game command line, kills the Mobs inside Spawn. 

There was a previous report  MC-14845 which was closed with only and explanation about ticks not being generated without the player present.  The person who reported plants not growing in spawn, had played with ticks and did not have a player at spawn. This is not a repeat, in my opinion, of that case, as ticks were not altered, and the player was present the entire time of the test inside Spawn.