Minecarts and chests disappear

hello. I subscribed to a realm server and have been playing happily with a friend for a couple of weeks, never had any problems.
Today, while playing as usual, I noticed that four of my minicarts were missing.
The server is in survival mode, and we used the four minecarts+chests we found in the mines and put them on the ground. I didn't leave them on the rails, so they moved a little bit here and there, but it wasn't a problem at all. I didn't do anything during play that would cause a problem, and my friend didn't touch those minecarts+chests either. Me and my friend didn't install any mods or other programs. Nothing else disappeared, just these four minecarts+chests. Unfortunately, we had all of our valuable items in those carts. Can you please fix this bug? Can we get our missing chests back? Thank you.