Your Store Still Has Old Product Variations

After the update to the new variants system (based on features) we apparently made mistake in converting them. They have all been converted but we still get this message very frequently:

Your store still has old product variations. They currently appear as separate products, without the ability to switch between them. To make them work as before the upgrade, convert old variations to new variations. It's easy and automatic.

How can we get rid of this message? When we click the link to convert old variants it turns up with no results.