My own airline had an incident recently where one of our senior captains became so disoriented taking off at night over water that he thought every flight instrument onboard had become unreliable (VERY unlikely). He dove toward the ground but fortunately managed to land before a disaster occurred. His First Officer stated that she knew the problem wasn’t the flight instruments, but didn’t correct the captain adequately.

You’re right, these experienced pilots should know better, but incidents do happen.