To add more context:
This doesn't seem to happen after a very short pause, but pauses of at least a few minutes.

It's impossible to replicate on demand.

I can't recall it ever happening with wired miked headphones, only with BT.

It's always a recently used audio app that starts. It's been Audible and Gone Mad, but never youtube, vanced, or VLC.

Force stopping and clearing the cache of the not wanted app does not (reliably, if at all) prevent that app from opening again after a pause in my Smart listening.

This behaviour is sporadic and occured on my LG G5, and now occurs on my LG V30.

What's the culprit behind this behaviour, and is there a way for me to stop this from occuring? (Beyond uninstalling Audible and GMP.)

Or is this something only resolvable by reporting the issue to the Dev?
In which case, which Dev? Smart's?

Thanks in advance for any help or guidance!