I typically drive mine 15-20 minutes before I do any pulls or drive it like a gorilla. This lets the whole system warm up front to back. Possibility your car wasn’t warmed up completely before you’re sixth gear pull?
Never owned a BMW prior to the Supra. Current daily happens to be a Toyota 4Runner, first Toyota I’ve owned. I don’t give a shit about a brand name, as long as it’s at the top of the list of being good at what it does. I find the dinosaur 4Runner to be delightfully analog in a digital world...