So I have half of my wheat field that was not growing at all for a while, I had the same bug with beets on another server (Not the bug where they refresh when you move something close. Those are really not growing, the soil sampler only see a dirt block.)
So I decided to dig them up, and this is what happens:
After restarting my client they where still there.
Other people on the server are seeing the same thing when they look at my field. Floating crops.
I was able to remove them by covering them with blocs.
Playing on version 0.5.6.1 alpha, on the other server too.
Additional remark: The bugged crops are in a big zone, but the zone doesn't coincide with the "claim areas". It's one off.