At 1400 rpm, under load, you're probably "lugging" the engine. The engineers have programmed the transmission to shift into the highest gear (within parameters) to maximize fuel economy. I have 2.0 engine and can feel the lugging at 1400 rpm and 60 mph. From the programming paradigm, what you're experiencing is probably "normal", although not optimal for engine performance, longevity, or operating comfort/convenience. From my experience, forcing a downshift to a lower gear makes the problem go away because the engine is then at a more appropriate rpm for the speed (mph). (Personal opinion: Too many engineering decisions are predicated on meeting the mandated Corporate Average Fuel Economy--CAFE--standards.) Good luck with your dealer!
2018 Premier, 2.0T, Cajun Red