Redbubble: Can I Upload in Multiple Windows?

Here’s a quick potential question that just popped into my head. What if you’re an artist with a large body of work that you want to post on Redbubble (I have 300+ designs), and you’re trying to find a way to upload it faster? You can open multiple tabs of the Redbubble uploader and upload designs in tandem. I’ve found that this works with Redbubble and Society6 all of the time, and you can try with all the other print on demand stores I sell on (some of them just have glitchy uploaders, and we’ll get to that) EXCEPT for CowCow. If you try to upload in multiple windows on CowCow, the designs will get crossed, and you’ll end up with a dress that has a sleeve from one design and a skirt, chest, and second sleeve from another. You might also get a product that’s missing panels of a design (on CowCow you choose an image for the background, front, back, and straps).