Can't get append argument to work in the wp_get_recent_posts function

I want to append some WP posts to the normal search function, but when I run the wp_get_recent_posts function (with the append and the posts IDs in an array), I don’t get the posts I wanted to append in the results. I’m not sure what I’m doing wrong.

If I remove the tag_id argument then the posts I want to append are included in the results. It seems that WP also filters the appended posts with the other arguments, is there any workaround?

$include = array(1, 2);

$args = array(
‘showposts’ => 10,
‘tag_id’ => ‘123’,
‘post_status’ => ‘publish’,
‘exclude’ => $current_id,
‘orderby’ => ‘post_date’,
‘append’ => $include,
);

$entries = wp_get_recent_posts($args, ‘ARRAY_A’);

Any help would be greatly appreciated – I’ve asked about this elsewhere but no one’s been able to figure it out. Thank you! ??