I see this at many (most?) clinics and seminars I've attended even at the level of the student executing the exact same error; usually the "my teacher teaches the exact same thing" sort of error and missing some important nugget of information due to the effort spent validating their existing training.
Yeah, I was just thinking about a rather stunning Aikido example of essentially the same problem that I recently saw. You know, my gut feeling is to avoid the anecdote and tell everyone to not trust anyone (not even me!) and go and see the best representatives of all the different arts that you can. That's what all really professional/dedicated martial artists do anyway, so let me encourage it, please. Even the "best teacher" you've ever seen and whom you may have modelled your life after can only put on their knickers one leg at a time.... i.e., they're human and may really NOT know everything.
Get Out There And Look.