sign disappair in the end

Signs in the end on reams disappaired.

What I expected to happen was...:
I expected that you won't disappair

What actually happened was...:
after everyone left the end, the signs disappaired

Steps to Reproduce:
1. buy minecraft
2. place a sign in the end (I placed them on dirt and obsidian)
3. leave the end
4. go to the end
5. signs are gone.

v 1.7.10
Minecraft realms
world: the end