An issue I've noticed now and then when I occasionally get disconnected, I'll be doing, say, a floor in the clockworks.
I might disconnect now and then, and that's a given, and your system seems to be almost competent in returning me and whom I presume knights/players with the same issue.
However I've noticed that it has issues now and then in returning me to my place, like about 2 minutes ago I randomly got disconnected and brought back to the login screen, logged back in immediately, and instead of returning me to the floor I was doing, it put me in the ready room, having wasted my energy.
It's not as-large of an issue for a party since the person can just join their friends but solo players (like myself) take this as a blight since we completely lose our progress.
I hope there is a way you can remedy this issue.
Normally when your SK abruptly disconnected, the game will consider you being idle. If you log back in within 15 minutes you should be brought back to where you were.
However there is an exception - when everyone in the party is dead, the game will put you on a timer (3 minutes IIRC). Since you are solo'ing the timer started immediately. When the timer ends you will be sent back to Haven.
I think that is what happened to you.