This has happened to me too. I have put holograms on my farm and near my portal, and they've all disappeared completely. It seems to happen when I log out and then back on.
If any of you didn't know, recently FallingSwords had heart surgery. He is currently recovering. He has been playing on TLC for about 6-7 years I believe, and he is the one who got me in to the server. As his nephew, I have coords to his base, and I have set up a chest for anyone to put a gift in to. It's optional, but I thought about it, and it seems like a good idea.
I have put forth 2 shulker boxes so far, planning to do a few more things.
It would mean the world to me if you could participate in this.
Mayor of Petal River