high end olive oil that is extra virgin first press organic blah blah and really high in polyphenols will have a very peppery finish. this is not the same thing as what you describe, but could be confused by some. the good stuff has the opposite effect and is highly anti-oxidative.

for that safflower to be rancid would require a long time in poor storage conditions. i am guessing clear glass and probably extended periods in a hot warehouse somewhere. light and heat are the enemy with oils as this increases oxidation(the process that produces rancidity). when it comes to oild, cool dark storage and when it is opened, use it up right away. many bottlers cap the bottle with inert gas in the air space to cut down on oxidation. once the bottle is open, the clock starts ticking. the older the oil, the faster the clock ticks. heat and light accelerate the process even further. i think heat is the worse ingredient for spoilage.

Rancid oil is smells bad - you can even smell it in nuts and seeds that have been on the shelf too long - I always smell nuts and seeds before I buy them. Anything that contains any oils at all should be checked first for it. Sometimes they have bulk items on sale that have been on the shelves too long and you can tell because it has that rancid smell. Always check it. I always put nuts and seeds in the refrigerator.

Recently I read an article in, I believe it was the New Yorker, about the corrupt olive oil industry. Apparently there is a lot of bogus oil on the market that has been colored and flavored to resemble olive oil. It's definitely something to think about and be aware of.

I would definitely take anything that was not perfect back to the market for a refund.