Negative cost of Raw material and import cost in Items cost & actual cost transaction view

Dear All.

It has been observed that system show in item cost detail negative raw material cost as well as imported acquisition cost in imported purchase transaction. Similarly, while reviewing the finished goods cost detail against batch in actual cost transaction review, we have the same problem of having negative raw material cost and imported cost.
Could you explain the reason of such behavior of system as this does not happen generally in similar other transactions

Ata