all beds where there, no one was destroyed...i buildt at every boss an new base with a bed^^, and there are still there.
I can sleep in theses beds, but when I die, I go back to start area, where all the boss trophies are.

I have this workaround, that I destoy the existing bed and buildt it new. Then I can create new respawn point. And then I respawn at this bed.
But why this happend to me, can no one explain. It starts at day 290 ingame.