The same thing is happening to me. The annoying this is that I'm developing a server and 3 hours of work can be gone in seconds. I have tried /save-all (even typing the command multiple times) and I've also tried saving through the Minehut dashboard - but still, for no reason, the server doesn't save the progress when I rejoin. I've heard of someone else having the same issues. I don't think this comes down to the /save-all because it used to be the way where you would just leave and everything would save. I'm not sure what's going on but I hope Minehut can fix this issue soon because it's really putting a dent on server development. Even though its bad that this is happening it's good to see that other people are having the same problem and it's not something I personally am doing wrong.