Recently I made a lamb salad and I bought pine nuts for the salad. AS being himself, he was munching on pine nuts later that evening when he felt like something.
Next morning he complained that his mouth had metallic aftertaste but he did not know why. He continued to eat the pine nuts during or the week.
He had that metallic aftertaste for next two weeks no matter what he ate. In the beginning, we thought it might me something to do with our vitamin supplements and I started Googling for the cause. I stumbled upon this article and the mystery was solved.
It states that a rare and seemingly random reaction to eating pine nuts can cause a metallic aftertaste. Fortunately, the reaction is temporary; in most cases goes away on its own in one to four weeks.
Just sharing our experience here and hope, it will be helpful.