Metallic taste in wheats only

I recently brewed a strong scotch ale and a dunkelweizen (all-grains) with two different results. I actually had submitted them to a judging thinking they were pretty much to style and was unpleasantly surprised by the results of the dunkelweizen. I had tasted it before the judging and it tasted very good to me. However, the comment they made was that there was a prevalent metallic taste that detracted from the taste. While it was still drinkable it was in stark contrast to the scotch, which did not have the same problem. After reading their comments I tasted it again and did indeed notice the metallic taste. I bottled for the competition but keg for myself.

Has anybody else noticed this taste from wheats? The wheat itself was about 55% and munich and victory made up the rest of the majority. I also used Hallertau hops, which were not used in the scotch at all. I kept temps and brewing techniques the same for both batches. Any ideas how to take steps to stop this metallic taste from existing in the future?

I remember about a year ago I brewed a German Hefe using a WLP platnium strain (can't remember the name or number) after I brewed the Hefe I pitched onto the cake (I know over pitching) for a dunkel. The hefe turned out great, but I did get the metallic taste from the dunkelm, I just attributed it to over pitching. I am at work so I don't have the recipe but I do remember using midnight malt (?) and munich, possible victory, fermenting around 70 degrees.

I thought it was kind of the style at first due to the dark grains but when the brew competition results came back with that I did understand that something had not gone right. I'm wondering if it could have been the wheat itself related to temperature of the mash or the rice hulls I included during the mash. Strange.