Cardex not getting updated during sales update

HI,

I have an issue when Sales Update R42800 is run, it does not update one random line for a sales order written to the cardex.

Its mostly happening for One Item/Branch and Customer Combination, where if an order has ten lines and during ship confirmation cardex would get updated and when sales update is run all those lines should be updated with RI document Number at that time just one random line does not get updated but the Amount on the R42800 report matches with that of sales order and posting to GL all looks fine except that the cardex Is not updated. We would have to  manually sql to update that one line with RI document Number, batch # and GL Date to match