7.1 Audio Channels Export Not Mapped Correctly

Problem
I've been trying to export 7.1 multi-channel audio properly from DaVinci Resolve, but I can't seem to figure out why they aren't mapped properly.

Workflow

• Source: MKV file with H.264 video and multi-channel audio (DTS-MA, Dolby TrueHD, DD, DTS, etc.)
• Since Resolve can't import many source audio formats natively, I import the source into Audacity, then export the audio as multi-channel FLAC, mapping channels in this order (SMTPE compliant): L, R, C, LFE, Ls, Rs, Lrs, Rrs
• Create a new Resolve project, then import the video from the MKV and audio from the FLAC file
• Create a new timeline and add both the video and audio (set to plain 7.1, NOT Film)
• Fairlight tab: Verify audio channels are mapped and play properly (they do, automatically)
• (Optionally perform edits in the timeline)
• Deliver tab: Export as H.264 Master, MKV file format, Audio Codec: Linear PCM (also have tried AAC), Bit Depth: 24, Audio Output Track 1: Timeline Track (7.1)

Result
Channels are never mapped properly, and are even mapped differently depending on which format I choose (although they are always wrong), which seems crazy. Resolve knows which channel is which, as evidenced in the channel names in Fairlight for Audio 1, as well as the meters for Audio 1 in the mixer as I play back the file. And I assume that since Resolve offers multi-channel audio formats for export, that it knows how to properly map this "known" channel config to a "known" format's channel mapping needs.

Test Files
I've attached a test project below so others might be able to reproduce the issue and help figure out what's going on. I've tested all input files (including the original MKVs and multi-channel FLAC files) using a Dune-HD player and a Marantz receiver properly configured for 7.1 output, and it all works great. It also plays from Resolve properly. But once Resolve exports it, the channels are messed up (one example: L and R might be swapped with Lrs and Rrs). You can even hear it on a stereo laptop.

You'll need to export your own output file from this project using the settings above since upload sizes are super limited, and I couldn't upload a sample.

I prefer to preserve the original audio fidelity, so I choose the much larger linear PCM over AAC to avoid re-compression. Multi-channel FLAC or DTS-Master Audio would be even better, but clearly Resolve doesn't support exporting those.

Thanks!

Which Resolve version and operating system is installed?

Is the Output Track on the Deliver page Bus 1? Is Bus 1 configured as 7.1 SMPTE?

Have you tried loading back the deliverable in to Resolve to confirm channel order?

Hi,

did you find the solution ?

Thanks