Valid_if Dependent Drop-Down Constraint

I created a dependent drop-down in the form they use to create 2D barcodes for boxes. The idea is if an item isn’t in the shipment, they cannot complete the form. I’m using the following expression in the Valid_if column of the 2D barcode creation table:

IN( [_THIS], SELECT(Work Order Form[FNSKU_ASIN], [_THISROW].[Shipment ID] = [Shipment ID]))

The problem is, if a barcode is scanned that is not in the shipment, the app freezes and I have to close and reopen it to continue working. Is there a problem with my expression? Of course they can select the box and choose the correct identifier however, with the barcode on the product, it’s quicker if they’re able to scan it.