Octopus Overlords

it's a Visa card from a bank that anybody in the us would recognize right away.

After some time the chip is refused at all point of sales. If I have the opportunity to swipe, the transaction completes just fine.
I call the bank that anybody in the us would recognize and they say "that's weird. Let us replace your card."
They overnight me a new card and all seems well.
Three weeks later and ...They chip is refused at all point of sales. .....

This bank is large enough that if they were regularly dealing faulty cards, there would be info on it and the phone service lady would not have been surprised. I assume it's something that I am doing that is causing this, but that's an assumption. This is the only card that I regularly use that has a chip.

What is causing this?
Ideas?

A bad batch from the plastic provider.

Are you keeping you card in a wallet or stick it in your pocket? Is it getting scraped or dirty? You can try cleaning the chip with rubbing alcohol and see if that fixes it.

Also, it's possible that some merchant where you regularly use your card has a bad terminal with a dirty slot that scratches the chip too much. You can try and figure out if the card seems to die after you use it at any particular store.

The readers at my grocery store hate my AMEX card. I also got a replacement card, didn't fix the problem. Probably too many boogers on other peoples' cards boogering up the chip readers. Oddly enough I never have an issue with my Visa card. I think it's a card manufacturer quality issue, AMEX must be cheaping out even though they charge the most for merchant fees.