$filter is not working

[Fauphi]

If I use $filter in my aggregation it returns an empty array:

const products = ProductsNew.aggregate([
		{$match: {'variants._id': {$in:[...]}}},
		{$project: {
			variants: {
				$filter: {
					input: '$variants',
					as: 'variant',
					cond: {$in: ['$$variant._id', [...]]}
				}
			}
		}}
	])

I'm using Meteor v1.11 and MongoDriver 3.6.0. If I try this query in RoboMongo it works.

Is $filter something that this package doesn't support?