MKV files with AV1 Video play as music file

Using 18.7 right now on my Nvidia Shield. I have to stay on this version for now.

I have some MKV files that use OPUS audio tracks AV1 Encoding, and KODI plays them as music files with no video. The files play without problems with VLC for Android.

Has anyone seen this before? Was OPUS AV1 support so new in Leia that the video player didn't bother with it?

EDIT: The issue was with the AV1 codec, which wasn't added to Kodi until v19.x (software), or really fully-implemented until v20.x

See my comment below for some additional detail