So this is why... I see, not sure why it happened, but definitely worth looking into, I did not mess with this file, thanks for the help, with both of things!
EDIT: I've also attached the log from the last time before the world started crashing, I don't see anything related there but thought I would add it for clarity. Before this question is asked, I do have a lot of space on my disk, more than 300GB is enough for small stats file to be saved.
Done!
Were in my horribly built house, in survival mode, standing, looking at the doors and walls, in company of my sweet dogs that protected me in my adventure. Then, I decided to close the game, thus used Save and exit button located on my magnificent menu, I clicked the button, watching the game save my horrible world, full of despair and emptiness. It has been done, the game saved my world that I would never be able to open again, leaving me alone in the main menu. Next, I closed the game and...
The last thing I did was standing in my house, not really much.
I think that this problem is only dependent on the lag, nothing else.
Had the same issue. My ops.json was alright in the previous snapshot and worked fine. There were multiple ops set.
After updating to new snapshot sadly when the server started up it threw the error I attached and as previous reporter wrote, it saved the ops.json file with single [ character. After restarting another error is thrown since a single [ is invalid JSON.