It depends on the internal management of the warehouse, if MSF must or shouldn’t finish the stock, and it depends on supplier packaging, this is impossible to change that for the momentthere may be several reasons for this:
The quantity ordered does not correspond to the multiple of the parcel, so the remainder will be in another parcel.
The item is the same but the batch number and expiry date are different. MSF-Supply is obliged (Good Distribution Practises) to treat each batch number or expiry date as a line and therefore these items may end up in different parcels.