When you verify an order with a large number of items on an iPhone or iPad, the order page may scroll back to the top after each scan. iOS moves the page to the field that receives the scan input, so you lose your place in a long item list.
Will a different browser help?
Not on iPhone or iPad. On iOS, every browser, including Chrome and Firefox, uses the same Safari engine, so they all behave the same way.
What to do
This is rarely a problem for small orders. For orders with many items, verify them on a computer or an Android device, where the page keeps its position. See What mobile devices does SKULabs support?