Pretty simple bug, If you sleep in a bed with the DoDaylightCycle Gamerule set to false it will still turn to day. I think this is a bug considering the translation from night to day by sleeping would be a cycle, which is what the gamerule is ment to stop.
MC-17784
DoDaylightCycle bed bug
Resolved
Fixed
0
Confirmed
DoDaylightCycle, bed, gamerule, moon, sun
Snapshot 13w24a
Snapshot 13w24b
Retrieved
Confirmed.