Dowsing Rods bugged

Post Patch - October
Using a 9% mercury dowsing rod, I located an iron node. I put a mining entrance on it... and it has 7% salt ore boulders.
Salt was the one purity I don't have a rod in... guess I will now; but I'm not sure what the point is... if purity of the rod is the only thing that matters... now.
I've heard that woo-woo is indiscriminate... but now dowsing rods are too?!
Using a 9% mercury dowsing rod, I located an iron node. I put a mining entrance on it... and it has 7% salt ore boulders.
Salt was the one purity I don't have a rod in... guess I will now; but I'm not sure what the point is... if purity of the rod is the only thing that matters... now.
I've heard that woo-woo is indiscriminate... but now dowsing rods are too?!