I set up a Minecraft Bedrock server on an Ubuntu Server VM running on my home lab Hyper-V server about a year ago for my kids. It is updated regularly (whenever the minecraft server process starts, and I perform manual updates to Ubuntu weekly).

My son complained that some of his chests have 'disappeared'. I got him to show me, and sure enough three of his large chests are invisible and inaccessible. They were working fine yesterday. There are still invisible 'boxes' where the chests should be, but right-clicking on them does nothing. Left-clicking on them attempts to mine them - you can see the little 'wood chip' graphics you would get from attempting to mine a normal chest. Two of these are full to the brim with several weeks worth of manually mined ore. The third was only partially full. As a test, I destroyed the one with the least contents to see what would happen - I was able to mine two small chests, but the contents were lost. The recovered chests could then be placed and recombined into a large chest as normal.

I'm not sure what could be causing a localised flaw like this - all of the other chests we've checked in the world seem fine, it's just these three that are next to each other.

Is there any possibility the contents of these chests can be recovered? It's possible I could roll back to a backup, but the problem is he spent the day mining obsidian - he has about eight stacks, so that becomes a choice of lose the chest contents or lose the obsidian. I'd prefer if there was just a way to fix the broken chests.