I am updating this post and apologize for the delay up front. Issues with the Inventory Valuation - WIP Report (Report 5802) continued to be identified into 2013 through additional case submissions and through additional internal regression testing. A rolled-up correction was released with the required changes to address issues with Report 5802. You can find the code change documentation in Knowledge Base Article 2786792:
mbs2.microsoft.com/.../kbdisplay.aspx
Thank you.
Tom Blaisdell