In a multiplayer game on a realm (where I am the owner), signs are behaving very strangely in the ender dragon area. I haven't yet been able to determine anything concrete but so far I have observed:

• Consistently, when a sign is hung on a wall made of end blocks, upon either leaving the end and returning, or quitting the game and restarting, the sign disappears. Other players are unable to see the signs at all. This happens 100% of the time that I hang a sign on an end block.

This behaves like something happened locally but didn't "stick" on the server side. There are no other sync or network issues happening, only the signs are behaving strangely. It is unique to the ender dragon area of the end world. Signs placed in the overworld and the nether have no issues, but signs placed in the ender dragon area are consistently misbehaving. I did not run any tests in the end city area of the end world.

I have only been playing in creative mode and have not run any tests in survival mode.

There are no mods or anything, the only extra thing installed is the Adventure Texture Pack.