Hi,
So while scouring the net for a nice Kowa I came across this one and noticed there was a slight discolouration in the optics. Seller sent me closer images and it's clear there's something in there. He says it looks 'gold in colour'. Not sure if it's fungus or even a crack or something benign, but worryingly, it's inside. Anyone recognise what it is? I have subtly marked affected areas with red arrows: