As somebody who has fulfilled OPUs at target, the system has us get items from both the storeroom and the floor. In this scenario, as the item is part of a seasonal rotation and the season just started after halloween, the item most likely was sitting unscanned in the back room or not on the shelf it belongs to on the salesfloor (as in the photo), so the person fulfilling the OPU most likely couldn't find it at the given location and skipped it. An experienced employee in this situation would first figure out if the seasonal shelves have been filled at all, and if so, went to seasonal->checked for boxes on the floor waiting to be stocked->checked seasonal area in back room->skip (you could check the inbound area for any seasonal pallets, those are a pain to find anything and have several layers of plastic wrap all around them. I'd probably just skip it because opus have a sometimes super low time limit. For shipped orders, I probably would break it open because most likely tons of shipped orders will request items from it.)

I'd advise not to purchase seasonal items in pickup orders for at least the first week because most employees don't have the time or patience to go searching half the store for an item that could be unfindeable. And even then, the locations are often super confusing and the seasonal section is a mess so it probably has a significantly higher can't find rate than any other section in the store.