There was a guy a few years ago who tried to live off grid. He died, having left behind a journal detailing his final days. In it, he logged the exact process you outlined above for various things he foraged, which included wild potato seeds. Turns out those things pass all the above tests, but contain a deadly neurotoxin that builds up over time (that even modern science didn’t really know about). Poor guy starved because he was too weak to even crawl.

nature be scary fellow humans. Be careful out there.

https://www.theverge.com/2013/9/13/4726722/into-the-wild-author-reveals-chris-mccandless-cause-of-death