1.14 Mobs are not spawning in normal difficulty

Hi I've start a game in 1.14 in normal difficulty I have switched many time in PeaceFull, Creative Mode, Spectator Mode but when I put the difficulty in normal (in gamemode 0) mobs are spawning next to mebut just around me when i walk 50-500 blocs in front of me there are no mobs 0 

I tried to walk 200 300 blocs but mobs are not spawning this a bug for sure

Also when I started the game ( in normal difficulty ) there are no mobs 0 like in peacefull and when i disconect reconnect there are mobs but there are just around myself and if i walk 50 blocs there are absolutely 0 mobs Please Fix there is a bug 

I have checked The gamerule DoMobspawning ... true (no problems)

 "           "      "  That i was in normal difficulty 

Maybe this is because i switched many time difficultys, gamemode 1,2,3 that there is this bug but please fix it.