NTT vanishing

While I was fishing, every NTT that comes to my character is disappearing at once! But the NTT returns when I far away from it, and disappear again when I go closer. I just try dying hope to reset the every character's state, but it still happens even I die, exit and go to nether! More even worse NTT vanishing happen! Please fix this bug, or I cannot continue on servival server!!