For some reason we are able to select bags that aren't empty for the Sew it Good quests. To avoid submitting one of your bags containing the rest of your bags for these quests, I suggest either removing the one that you want to submit from the rest of your bag tunnel, or making the one you want to submit the last bag in your bag tunnel by removing the smaller bags / items. For the pilgrim backpack, this will make it's weight 2.9 Kg (if its empty). The rest of your pilgrim backpacks will be much heavier from the other backpacks inside of them. You can right click and inspect the backpacks in the submission menu and select the one with the least amount of weight as shown in the linked picture.
This is far from ideal and could be fixed by BSG not allowing non-empty bags to be submitted, but until they do that, this is how I avoided submitting my bag tunnel for this quest.
