Resolve 15 Beta 6 syncing dual-system sound not working

I have been using the 15 beta for a while and have had a consistent issue when syncing dailies that were recorded in a dual-system environment using a variety of Tascam and Zoom audio recorders and files form Canon cameras and Atomos recorders. I found the directions for syncing audio via waveform and have tried it both with append tracks and without. When I do that, one of the following will happen:

1. The audio and video will not be synced. When I drag the video clip into a timeline, the embedded audio will be there with it and the dual-system audio will be in the timeline's audio track after the embedded audio.

2. The embedded audio will be replaced by the dual-system audio file, but when I try to play the clip back either in the media browser or a timeline, it will be silent. If I drag it into the timeline, I will see the file name of the dual-system audio and a waveform, but no audio will play.

Has anyone had this happen and/or know a fix for it? failing that, is there a way to translate a Resolve 15 beta database so I can open it in Resolve 14.3?

UPDATE

The issue is still present in my copy of 15 Studio v 15.3.0.008

I had the same problem. But when I try to play the synced a disturbing sound is heard. Seldom it stays muted.