Thinking it's probably something you can expect on any of the current tall frame road bikes that likely are not made with the idea of going to shorter cranks and, as that requires raising the seat post, which in turn shifts body weight back, increasing tire size by 3 mm to increase the trail has for me been a practical work around. Going back years, my old Trek, even with slack head tube angle, still had issues with loaded panniers on the rear and the only thing that made it rideable was a loaded handlebar bag.