Search by _id field

Hello again. I am having a trouble using the with_scope tag. I need to filter by _id.in: array of ids.

Looks like a normal case, but in the MongoDB logs I see {"_id" => { "$in" => false } } and it crashes.

On the other hand, if I filter entries by id.in: array of ids , the query looks good but I get no results.

Are there any prerequisites for such behavior or is this a bug?