I have a similar issue with the difference that I don't pass spctl for some mysterious and arcane reason.
Have you stapled the notarized app with xcrun stapler staple?
Also how are you distirbuting the app? Compressing the app before sending (.dmg or .zip) might break the signature.
I'm really frustrated with Apple's Gatekeeper blocking my correctly notarized app. They should at least provide clear verbose errors to identify the origin of the problem. I spent more time trying to debug this than building my app...
Topic:
Code Signing
SubTopic:
General
Tags: