Cannot import XAVC S/AVCHD with Premiere Pro CC 2019
the same problem encountered here with a different sony handy cam. 
I don't know how to solve the issue but I have a way to get around it.

import both AVCHD file &amp; MP4 file in Premiere Pro and open both in a sequence.
now use video of AVCHD file &amp; Audio from MP4.

\\ I don't want to use video from .mp4 file because its resolution is lower than the AVCHD.