String disappearing on realms

While building the Behemoth (enderman xp farm) i noticed the endermen were getting stuck on the spawning pads when i went to check i noticed that the string was missing the tripwire hooks appeared like if they were conected by string but there was no string there. I knew that string desapearing was a known problem while changing versions but since i started the building on 1.11 I believe this is a new bug.