I am getting the following symptoms in Adobe Premiere Pro CC 2018 and CC 2019: video recorded on a Sony AX-100 in AVCHD mode starts off in sync on the Premiere Pro timeline but by around 15 minutes (suddenly?) goes out of sync with the image ahead of the sound by between 0.15 to 0.44. When rendered to a file, they remain out of sync.
Here are some more facts:
There are no transitions or effects in the timeline.
This has been replicated several times using the onboard mic and using a wireless Senheiser ew100 system
These same video files are perfectly in sync in VLC and in Movie Studio 14 (Sony Vegas).
The same out of sync problem occurs when in AVCHD (frame rate 60p), and AVCHD (tested with frame rate 60i Standard [HQ], and frame rate 60i Highest Quality [FX])
All flavors of AVCHD use the audio codec A52.
When recording on the Sony AX-100 in the other file formats -- XAVC S HD or XAVC S 4k -- the video files are in sync in Premiere Pro CC 2018 and CC 2019.
The XAVC S HD or XAVC S 4k settings use the audio codec MPEG AAC Audio (mp4a).
I deleted all the audio cache files in the relevant appdata folder for Premiere Pro CC 2018 and CC2019. I also imported one photo at a time and followed all the recommend steps from Unofficial Premiere Pro Troubleshooting Guide. Nothing solved it.
I also ensured that Premiere Pro picked the correct project setting based on the video file dropped into the timeline.
All video files were transfered to my PC via a card reader and the default Windows 10 "Import photos and video" app
Can we assume that the problem is the A52 audio codec? All lfavours of AVCHD on the Sony AX-100 use that audio codec. But the two other video modes (that work fine) use the mp4a codec.