Activedataprovider set limit inside of query with union but should outside

What steps will reproduce the problem?

$query = Product::find()->where(['id' => 1]);
$query2 = Product::find()->where(['id' => 2]);
$query-> union($query2);
$provider = new ActiveDataProvider([
'query' => $query,
    'pagination' => [
        'pageSize' => 12,
    ],
]);
$provider->getModels();

What is the expected result?

(SELECT * FROM product WHERE id=1) UNION ( SELECT * FROM product WHERE id=2 ) LIMIT 12

What do you get instead?

(SELECT * FROM product WHERE id=1 LIMIT 12) UNION ( SELECT * FROM product WHERE id=2 )

Additional info

Start by reproducing the reported ActiveDataProvider query with the union and pagination snippet, then trace how getModels() applies the page size and how the union is rendered. Done means the generated SQL places LIMIT 12 after the complete UNION rather than inside the first SELECT.