I have found that my Premiere Elements (15.0 on Windows 10 64 bit) doesn't seem to like importing GoPro files that have been auto-rotated 180 by the camera. I have to re-save all of the files (mp4) using other editing software first! Has anyone else found this?
I've just encountered this very same problem importing footage from my Hero 7 in to Premier Elements (V15). Only videos recorded with the camera the correct way up will import, regardless of the rotation/lock settings on the GoPro.