2019 Expedition 7,000 miles. Out of nowhere it beeped when I open/shut door while running. Flashed "no key detected" but the Fob was in it. I tried both fobs and it still did it periodically. Next day, the one fob wouldnt unlock or lock it. Tried the other and it worked......... Thinking bad fob battery..... until the other one didnt work..... and vice versa. Now, 2 days later and they are working fine. No code popping up. Thoughts?