I am new to Microsoft Dynamics NAV and I am hoping that someone can shed some light for me. 

We have a situation where a few cost per unit are showing up as a negative value in our inventory valuation report only. Any other report that I generate, shows the correct unit cost (i.e it matches what is in the Item Pricing details).

I can't figure out why is would be valuing it as a negative value.  

Does anyone have any suggestions on where I could start to investigate this issue?