We're having the same issue, but live on the production App Store. 100% of user downloads are failing to install. I can confirm that increasing the watchOS minimum deployment to 8.7 worked for us. Very frusrating, several $k lost. All tests worked beforehand and passed App Store review.

@nachojackson solved the issue for us. We had a group new the edge of the icon canvas with the "blur" effect enabled. Disabled the blur which seems to stop the auto-compiled SVG from having an alpha channel.

I have a similar issue... I have an update that is Pending Developer Release and the only way to do a final test on production in-app purchase receipts etc. is via promo code... App Store confirms the promo code and says the app is downloading, but it just never downloads. I've tried on multiple devices and accounts, no error, but no app downloads. 🤦🏻‍♂️

Everybody still having this issue? The only way to test production in-app purchase receipts etc. is this method before releasing. When I try, I get a confirmation that the app is downloaded but it never downloads, and the code becomes used so you can't try again. Tried on multiple devices and accounts.