This has literally been a thing since forever.
If everything in your house fails to load, it's solvable by walking out of the level and back in a few times. It's nothing they can do anything about.

If you're talking about individual items 'disappearing' you should report those individual item types to an admin. I've seen the shower and christmas sign (recent) 'disappear' when placed from inventory and both were reported and function properly now.