Mislabeled pouch

Contract medical device manufacturing company here:
-The customer ordered ×××× product
-The customer received ×××× product through lot number yyyy
- 6 products ×××× in one box is how it was packaged
- The product itself has marking and was also packaged in a pouch before packing it to the box. Meaning, Pouched product was being packed in the box.
- 1 pouched product in a box of 6 pouched product had incorrect part number on the pouch but correct part in the pouch. Pouch was mislabeled.

My thoughts after an initial investigation is :
- Line clearance was not followed well
- The inspection plan was not followed well
I did observe from the the Part Specification that the incorrect part number was directly under the correct part number which makes me believe that may be the incorrect part number was printed in advance?
What could be a better corrective action for this? Other than training operator on line clearance and Quality Inspection. Does it help to make the inspection of the label on the inspection plan where it points to the part number area of the label 100%?

Do the parts look different enough that a picture placed in the 'holding' bin would help identify the parts? Is there a weight difference that would allow that type of measurement to verify and would it help?

For me, training is not a great corrective action. A good 'add to corrective action" but do you performing this specific training to new employee's, if no, this CA can be repeated 1-2 years from now. I have never actually done this personally, but I have talked to a quality person who had a system that the UPS box had to fall within a specific weight otherwise a red flag was raised. This type of thing might work for you (not sure about this personally but that is probably due to the type of manufacturing I am in).