Hasselblad - Strange Glare with Polaroid Back

Just picked up a Polaroid back and took a few frames. I was surprised to see these unusual "glare frames" in the corner of the images. My guess is it's a sealing issue with the back itself (tough to complain about a $50 back off eBay) but wanted to see if you all had any other ideas.

If it's indeed the back and not advertised as such, I'd try to get a refund from the eBay seller. I also bought mine for $50 off eBay, and haven't encountered any such glare or ghosting. With FP-100c prices these days, extensive troubleshooting could get expensive very quickly.