You can find prop 65 warnings on basically anything heated to browning too. Coffee, cooked asparagus, bread, the list is gigantic: https://franzbakery.com/HTML/prop65

I’ve seen the prop65 warnings about reproductive health on Japanese canned coffee and tea, but I’ve never seen these warnings on any other canned drinks here in the US

Maybe they are imported through California? Most canned drinks probably come from Ohio or New Jersey or something.

Brazil nuts are like that as well. The nuts themselves are ok but how they're grown causes them to contain too much selenium which can be toxic over time.

Mercury in fish is another doozy.

The physical store likely has a warning saying they “contain chemicals known to cause cancer.” Because these warning signs are so ubiquitous in California you probably just miss it when you go to the brick & mortar.

Quite possibly, but it seems like if you can just have one big sign in front of the store, then you could just have one sign on the bottom of a website. Here there's a specific warning on the organic frozen spinach.