I was hosting a Survival Minecraft server. Me and ~6 other players setup a ground zero location near the spawn point and mapped out the full region and began excavation from a central point.
We worked at it for ~8-10 hours yesterday - just playing having a good time. We got on today, all started playing around and "cliff diving" when we died it threw us into a completely different off map location. I used gamemode 1 to give ourselves a compass and map and the compass again took us to a completely different zone nowhere near our original spawn point. In addition we couldn't find the original starting map.
I can't host a server until I can figure out why, this has happened 3 times since! We kill ourselves after about 24 hours and it puts us in a different zone - but on the same map. I'm not re-creating the server each time. It remembers where we are are until we die - than the spawn is random...
I just googled how to make a new spawn point, and ended up here. My boyfriend and I created a server so that we could both play together. We went mining, and found quite a bit of diamonds, gold, etc.. also had enchanted diamond pickaxes. We were really close to being out of the cave when we died. So naturally, our first thought was "No problem. Our house is right by our cave, and we slept in the bed, so we're good to go." - Too bad that we came across this bug as well and lost everything we had. We had to go into creative mode as well, and we enabled the flying option. This happened more than once, too.
Until this bug is fixed, it looks like I'll just die (while holding nothing, of course), and when I go back to the spawn point, I'll fly to find which way is home, and make a powered mine cart. It wasn't too terribly far from our home, but it was still far enough that if we had to walk there, our stuff would be gone by the time that we could get to it.
Please, let me know if you guys figure anything out.
I tried to take a shortcut to kill myself so that I would spawn where we kept spawning by typing /kill.. and now where I died is my spawn point. I kind of glitch out though and can't move until I either break the block below me or go into creative mode, fly, and then switch it back. It might be a little annoying to have to tell the server that you're playing in creative mode, and then back.. but at least it works, and it puts me in my house instead of a long ways away.
Looks like the only way to counter this is a backup of your maps before and after the server is turned on (which means 2 backups).
Which is majorly annoying but hey, it does help when you get a spawn reset.
I have encountered this same issue. I'm working on a way to change the spawn point by going into the level.dat with NBTedit and changing it that way. I haven't tested it yet, but would like to. And for people loosing their creations, mapping programs are great for finding your way back. I recommend Minetographer.