Thanks for the heads up!
I have a guess - if you were running the normal Raspberry Pi 3 on the same resinOS version, you’d see the same error, it looks more like a resinOS 1.x <-> 2.x thing (maybe, just maybe that I think we are not running the audio module by default anymore, an issue that was discussed before). Is your code using audio at all? Or I wonder why ALSA is started there?