Shortcode stopped working, error in log

Hi,

thanks for the plugin, its been very reliable over the years.
We have a shortcode like this:
[player id=8130]
which no longer emits any markup.
In the Apache error log I see:

Got error ‘; PHP message: PHP Warning:  foreach() argument must be of typ
e array|object, null given in /home/caice_devv2/caice2.akriga.co.uk/htdocs/wp-content/plugins/html5-audio-player/shortcode/player.php on line 66;
which looks very much like a smoking gun.
foreach ($selected_audio as $id) {
where
$selected_audio                 = $meta(‘selected_audio’);


wp post meta get 8130 selected_audio
returns nothing.
Happy to help with debugging since I can recreate this at will.

TIA