Whenever I open my survival world after putting ornaments on my tree, the ornaments disappear and the tree turns green. Does anyone know how to fix this or is it just a bug?

My friends and I have had the exact same problem as well. Ornaments will stay on only for the entirety of the login session. As soon as you sign out and sign back in, all ornaments disappear.

Additionally if your Christmas tree was white, it'll turn to a blank green Christmas tree as well after the next time you log back in.