Premiere Pro 25.6.3 and Canon C70 XF-AVC Audio Issues

I have an audio issue that is baffling me; perhaps someone else has encountered it and knows what's at play.

I recently shot a multicam project where the A-Cam was my Canon C70, shooting in XF-AVC, YCC422 10-bit 4K. System frequency was 59.94 Hz, audio was set to LPCM, 24-bit, 48kHz, which gives 4-channels of audio, though active audio was only passing to channels 1-2 (ch 3-4 were recording dead air). TC was fed via BNC on the A-Cam (i.e. we were not striping an audio channel with TC).  The B-cam was irrelevant, as it's not giving us the problem (but was also XF-AVC, etc., etc.)

At the conclusion of shooting, we checked playback of each camera for audio and video playback; all was good. We also previewed the files using Canon's XF Utility on the laptop; again all is good.

When bringing the files into Premiere Pro and preparing the multicam sequence, there is NO audio showing for any channel of the C70 footage! I have tried the Audio Channels / Interpret Footage; tried transcoding the footage using Media Encoder - using both ProRes and MXF Op1, transferring multiple ways - both direct from the card and using the XF Utility - all with the same results.

I went back to the XF Utility and checked the file, and the playback is perfect. Audio is clear on ch 1-2 and shows in the meters (screenshot attached), but disappears when imported into Premiere.

To solve the issue for today, I was able to import the clip into Tentacle Sync's timecode tool and export an audio-only track with timecode embedded into it, then sync that back with my multicam sequence. This takes substantial time and is not feasible to perform on every project (but will get me out of a jamb today).

Any thoughts on what might have caused this to occur? 

System info - Intel Core i7 evo, Win11 Pro, 32GB RAM, NVidia RTX 4050

Premiere Pro 25.6.3 / Build 2

Clip specs attached.