Cannot update quantity X with new dimensions

This error message is the result of trying to update registrations from the device on a picking list registration with reservations. These reservations can be physical but also based on ordered items. If the picking list has reserved ordered items this means it has not been received into the warehouse. 

Solution: 

There are two solutions. Either receive the items and process the registration again, or change the policy about the reserve ordered items. The parameter is a standard AX/D365FO parameter and is found in "Inventory and warehouse management parameters".