If the app is signed correctly on your computer, make sure the zipping command you are using is not destroying the UTF8 encoding and the signature is then seen incorrectly on your submission to Apple.When preapring the zip archive for notarizaion use ditto and "–sequesterRsrc" option./usr/bin/ditto -c -k –sequesterRsrc --keepParent "$APP_PATH" "$ZIP_PATH"Regards,Conor

Thank you GregVideoVillage. Unchecking "Upload debug symbols..." worked!! I mean it's abad fix, I like getting the crash reports already symbolicated, but at least I can get updates in the App Store for Big Sur. I had downloaded older version of Xcode and actually managed to fix the bug by using Xcode 11 command line tools in a script. But when uploading to the store from within Xcode it ignores the set version and uses the latest. Still present in Xcode 12.3. In a follow up, I have to restart Xcode between uploads as won't find a file on the second try. The file is always the quicklook generator and spotlight MD Importer. As I think it might be what was giving the original bug. It finds it once, but not twice and hence why the URL was empty and the crash that follows.

Try in Terminal: defaults delete com.apple.dt.xcode DVTSourceControlAccountDefaultsKey defaults delete com.apple.dt.xcode IDESourceControlKnownSSHHostsDefaultsKey sudo killall ssh-agent

See https://developer.apple.com/forums/thread/665666, fixed the issue for me. Specially changing to RSA SSH keys.