2015 f150 2.7, When started from dead cold, usually the first drive of the day. The motor will over Rev slightly and CLUNK into third gear. There can be 1000 shifts up or down into third after that and it's smooth as it could be. Anyone know the cause or remedy?

 

mine has an occasional issue when shifting from 4 to 3. It happens so infrequently that I just ignore it. I can't replicate it so I'm not going to bother to take to the dealer
https://www.f150forum.com/f118/4-3-shift-noise-342138/