Was playing realms first time in nether with this server and after leaving the initial area blocks turned invisible along with some zombie pigmen. Not all blocks in the nether did this and I'm unsure what block type"s" it was and I could see the zombie pigmen for the most part however when I shot an arrow at a ghast I hit an invisible pigmen which then had the others attacking me. after that happened the pigmen on the invisible blocks started to attack and some seemed to get stuck with twitching heads... I was then attacked by invisible enemies. I left the nether only to have a loading screen that didn't go away. I fixed the loading screen by closing the app and reopening it the rest of the realm seems normal haven't tried going back into the nether.