I too have the same problem where hours of build are gone. I respawn back in the same space where I was when I started the build the previous day each time. This has happened the past week and a half now. I have tried creating one small thing, disconnect from the Realm, and reconnect. The build is there and appears to "save". I have also repeated that and quit the game to re-launch and it appears to "save". But if I "quit" for the night and come back the next day it is all gone.
I too have the same problem where hours of build are gone. I respawn back in the same space where I was when I started the build the previous day each time. This has happened the past week and a half now. I have tried creating one small thing, disconnect from the Realm, and reconnect. The build is there and appears to "save". I have also repeated that and quit the game to re-launch and it appears to "save". But if I "quit" for the night and come back the next day it is all gone.