Jehovah's Witnesses: Has the Watchtower ever taught anything that was Scripturally incorrect?

It's rare to see a JW like Ethan that can just admit they have been wrong. Probably because it opens a can of worms. If they have been wrong in the past, what are they wrong about now? If you know they have been wrong in the past it doesn't make sense to support 100% of what they say now does it?