Zero balance account have balance

Hello,
I are using ECC6.0 , I are facing a problem in Document splitting. We have assigned Profit Center based document split. At the time of documents splitting the entry passed to setoff zero balance in Profit center the offsetting entry should be passed but instead of this it is passing only one Dr or Cr entry in Zero balance clearing account.
Eg

Expected entry :-
Account Amount Dr/Cr     Profit Center
Stock Raw Material A/c    500     Cr     PC1000
Material Consumption A/c    500     Dr     PC2000
Zero balance A/c     500     Dr     PC1000
Zero balance A/c     500     Cr     PC2000

Actual Entry passed by system
Account Amount Dr/Cr     Profit Center
Stock Raw Material A/c    500     Cr     PC1000
Material Consumption A/c    500     Dr     PC2000
Zero balance A/c     500     Dr     PC1000

Which is creating problem in accounting and trail balance is showing amount in the Zero balance clearing account. Now I have to know how I
can prevent & correct the problem.

Request you to please provide solution from your side for this.