I took up running 5 years ago. After a year, and after reading several articles, I switched from heel striking to forefoot running with the forward lean at the ankles (not a bend at the waist). It took a few months to get used to it, but my running became faster, more efficient. But, my calves became extremely tight running with this style, even when trying to stretch regularly. To cut to the chase, I subsequently endured regular cycles of being able to run for about 6 months at a time and about the time I would ratchet up the intensity, the tightness in the calf / Achilles / arch chain would ultimately result in plantar fasciitis in one or the other heel or in one of the arches. Then I would have to stop running for 6 months for the PF the diminish before starting the running cycle again. That is until December 2017 when I read about an Achilles stretch that has changed my running. I now do intense workouts without the accompanying feeling of my lower legs and feet slowly tightening to a breaking point like a tightly wound rubber band. I do these stretches multiple times a day, every day, standing on one foot at a time on a stair, with heel below stair in a 30 second stretch with leg straight and 30 seconds with knee slightly bent so I feel it deep in the Achilles. All this is to say that if the Nike Vaporfly 4 shoes push heel strikers forward more into a dorsiflexed foot position more akin to mid or forefoot strikers, then I can see how the Vaporfly 4s are changing people's running form slightly and causing your symptoms. Try the Achilles stretches several times a day to see if it helps you as much as it has me. Don't give up on the Vaporfly 4s. I just ordered some and am eager to try them, based on other peoples' experience. Here are 2 links to articles about the calf/Achilles stretches: http://drpeggymalone.com/stretch-calves-important/ and https://www.balancedrunner.com/the-most-important-pre-run-warmup-a-calfachilles-dynamic-stretch/