The only other thing is that I bought a different brand of protein powder for my morning smoothies. To be sure, at first I thought the protein was the cause of this, because the taste started the morning of my first smoothie with the new powder.
But I have not used it consistently each day since, just on the chance. Maybe I will go back to the old protein for a week and see what happens?
I was on on pred only once, for 2 years, but I was off it by 1988. I do not remember metallic taste being an issue; and though it was years ago, I think this would have stuck in my mind.
OK, maybe it's the protein!