Thanks for suggestions, guys. I didn't have time for a sealant to cure before predicted rainstorms, which is why the duct tape. Not sure how it will hold up, though. If still a problem, probably will go with sealant.
I sealed every thing I could with caulking, but gorilla tape over the sight window stopped the leaking. TH sent me a solid plate to replace the clear plastic one(at no charge), but since the tape has worked I haven't replaced it yet.