I've tried with the latest Safari 14 beta 3. The issue is still there. Nobody has a solution?

(edit - no answer)

I ask this question because I'm unable to load a Safari WebExtension on an other computer when my host app is successfully notarizes. My only hypothesis is the App Store distribution is mandatory. Funny note, when my app isn't notarized I can load the extension after I clicked right > Open on the host app.