I created an Ice farm that is 6x32.  At first it worked just fine.  Ice formed as expected and in not very much time it filled the whole area.   I mined it out several times.   Then all of a sudden it stopped working.  took out all the water and replaced it again with source water blocks.   It would only form water in 1 column starting from each end.  I tried several times to redo it and I could only get the one column to form.   I created a couple more troughs 2 wide and they would not freeze either.   I gave up and went to bed.  I logged in the next day and without making any changes it started working fine.  It worked fine all day long.   Some other players on our sever also built one and it was working fine for them as well.  Then in in the evening it stopped working again and would only produce the one column of ice in my 6x32 trough and would  not form any ice at all in my  2x2.  Same results for the other players.

We went to bed and this morning logged in and it is still only producing 1 column of ice.