Arelith

I noticed that imbue weapon used on a shield (abjurant champion ability) causes a slight error.

It is: Bad Strref (temporary), and I beleive it has to do with the :

"Grants Elemental Damage Immunity and Damage Reduction equal to to 1/2 the Spellsword's #Imbue Armor bonus" (from wiki)


edit: tried to upload screeshot as attachment, but it says server attachments are full.

Could you upload the screenshot on Imgur? :)

Thanks for the screenshot!
What you've observed is not a huge problem, the "Bad Strref" is part of the Damage Reduction property. I believe we have expanded some item properties with additional parameters a while ago, and these extra parameters being empty (which would be NWN's default value) is what causes this message.