I managed to find a possible fix to this. Namely, in the kodi VideoPlayer.cpp file, I removed the line:-
FlushBuffers(starttime / 1000 * AV_TIME_BASE, true, true); (See my earlier post).
and remade the image from a forked CoreELEC - that’s the only change from CoreELEC master.
Now, the audio is heard immediately upon resume. So far I’ve not had any issues.