Synchronization problem on blackberry/sup 2.0

I am having problem while synchronizing data on blackberry. I am using SUP server 2.0.

Suppose I have 15 rows of data on my SAP sever corresponding to one MBO.

On first sync i am getting 14 rows in my local database,

on second sync its 13 rows,

on third its again 14,

then 13,14,13,14.......

what could be the problem?