Meeting and discussion with Kim, Sir Rey, John of ICG, Jovie, and Nina. those highlighted in green the SKUs that were only reflecting only 1x in IAS but were received 2x in JDA. These are SKUs with 2 seasons, example SKU 121857 is both in SS20 and FW20 and is in 2 separate PO#s. The total quantity to be received for this SKU should only be 24 pcs = 12 pcs for PO#3418 and 12 pcs for PO#3430. However, in IAS it is reflecting only 1x under PO# 3418 as 48 pcs and no entry for PO#3430. In this scenario alone there is already a discrepancy of 24 pcs. As per the store, it wasn't wrong encoding because it is reflecting correctly in JDA. 
Those in red fonts are the SKUs with no entry reflecting in the IAS arrivals report, while those in black fonts are reflecting a significant difference from the actual quantity received by the store vs the entries in IAS. See SKU 121856. It should only be 7 pcs as received by the store, but in IAS it is reflecting double with 14 pcs. Sir Rey found the reported SKU does have multiple records in INVUPC that cause to duplicate also the QTY in the arrival summary report. This happens because an SKU does have a chance to have multiple UPC's but they need to identify the UPC that should be deleted for us to display the correct QTY in the Arrival Summary Report.