Infuse will play recent .mkv files with multiple audio at one place, won't in another

Long-time Infuse user… I’ve been ripping several of my music BD’s recently and including most if not all of the original audio tracks in the resulting mkv’s. The Infuse installation on my 4K AppleTV in my home is refusing to play them with the “Failed to open input stream in demuxing stream” error. However, the previous-generation AppleTV at a vacation home, reading off a local backup of my home server, plays them with no issues.

Exact same content, different hard drive source and slightly different target device, (presumably) same software. I’ve tried rebooting the AppleTV and deleting and reinstalling Infuse, no luck.

Representative Media Info output on one of the files. Some of the rest (not all) contain Dolby Atmos audio tracks.

Server in both cases is an older Mac streaming over SMB.

Looks like the ‘fix’ is remuxing the files in MKVToolnix.

Still no idea why the original files work fine in one instantiation of Infuse and not in another…