Bamboo is floating and growing abnormally

This save was created in 18w43a and I use it to test new features, it was no problem to open this save in 18w43a to 18w46a, but today I opened it in 18w47a, I saw many floating bamboo, and if I destroy them, they will grow up again in mid air, so I have to change RandomTickSpeed to 0 to stop them to grow continue. Please fix it