This is about multi-player mode; for a single-player discussion see Night-through sleeping in single player: 5 days?.
If one goes on sleeping in multi-player, the outcome if different according there are other players or not:
- If there are other players, the sleeping goes on indefinitely in regular game time.
- If one is the only player of that server, the sleeping quickly goes through the whole night and in a few (real time) seconds one awakens at the morning, exactly as in single-player mode.
Note that the case 2. is affected by the same 5-days-later bug described for the single-player mode.
Is this difference intentional?