infoCube - Vendor Account Group(navigational attribute) inconsistency

Hi All,

An infocube(purchase) which have vendor account group as navigational attribute.

Today when we run the query with comp code(1000) and fiscal yr and period (001.2014).. it is showing all data except for one purchase order(XXXX34), this is getting suppressed although it matches the query selection criteria.

Due to vendor Attribute" Account Group"  this is some how  not getting shown.If we check the same in cube, and selecting the order and vendor without vendor account grp field the output displayed while if we select the vendor account group also .. the result disssappear.

Surprisingly it vendor account group is working for other orders..

Please suggest ..

Thanks
Saurabh