Perfect example of being an audiophile so long that the "reasonable explanation" that we simply hear differently throughout the day, that the mood affects how we perceive things is no longer necessary. Not even for an engineer. Turns out Burn-in is not only real but it is not even permanent! A component will return to its original unbroken in state! I don't meant to laugh but it is just what this hobby does to us.
This is Paul McGowan.
Is Burn in Real?
https://youtu.be/lJFnlDTtsBA