Hi..
I doubt that after you activated ML at 01 2014, you
occurred MM transaction using period 12 2013.
You should review material’s transaction using t-code ckm3 to find mm document which
have posting period 12 2013 and input period 1 2014.
If you have MM transaction of period 12 2013, you should
close ML of period 12 2013 using note 361236.