My friend is falling through unloaded chunks

My friend joined my realm and there was one spot where it looked to her as if there were a chunk or two that were gone in one spot when it looked fine to me. when she tried to walk over what looked like a drop into the void for her person she fell out of the world and died with all the really good stuff I had given her. to me in looked like she just tp through the ground into the void. no doubt one of the weirdest glitches ever