get_post_meta not returning results

I’ve had to write a workaround for my site because Polylang seems to be affecting the wordpress get_post_meta function.

I was trying to get results of a post meta relationship for a specific post id.

On a different language other than en_GB it seems to stop the function returning an array of results.

$meta_key = "your_key";
$meta_key = "your_post_id";
$sql = $wpdb->prepare(
"SELECT meta_value FROM {$wpdb->postmeta} WHERE meta_key = %s AND post_id = %s",
$meta_key,
$post_id
);
$related_ids = $wpdb->get_col($sql);

this strangely provides a different result than using get_post_meta.
I did not want to sync my custom fields as it creates a huge overhead.

I don’t know if this is a bug or by design.