If it is any consolation conditions like you demonstrate are not at all so rare and I have had customers that were initaly sent away with “could not duplicate” written on their repair order return with video of the symptom (they all feel like they won the lottery when they get the cluster acting up on video). What they really get is me tearing their car down a microscopic level looking for the cause of this “once every 500 mile and just for 30 second interval” time period that the cluster wants to act up. No matter how good the guy is you really don’t want someone tearing up your car so deeply chasing this problem. Just like people say a car is never the same after an accident repair, well there is a bit of the same going on when I have your dash, you instrument cluster harness and your engine management harness tore out of your car. I try very hard to put things back together just like they came out (but with the problem fixed) but this is a goal not often realized.