Can't get the columns of galleries when the user set the column number to 3 if there are 2 galleries?

Question

I'm detecting if the user has a gallery in his post:

$gallery = get_post_gallery( $post->ID, False );
$gallery_images = explode( ',', $gallery['ids'] );

And at times I'd like to see how many columns it has:

var_dump( $gallery['columns'] );

This works for 2 columns, it returns 2 but if I were to set the columns to 3, it breaks, throwing the error:

<b>Notice</b>:  Undefined index: columns in <b>C:\file.php</b> on line <b>45</b>

Note that 4, 5 columns work just fine, but 3 won't. This only happens when there's a second gallery in the post.

How is this possible?

Answer 1

OK, I just tested this a little further. Indeed, if you select 3 columns (the default WP gallery column count) and do a var_dump( $gallery ); you will see that there is no column key in the array. (like for example with 4 columns ["columns"]=> "4").
You can maybe do something like this:

$gallery = get_post_gallery( $post->ID, false );

if (array_key_exists( 'columns', $gallery )) {
    echo $gallery['columns'];
} else {
    echo 'default WP 3 columns';
}