Since upgrading to macOS Big Sur every time I run an React Native app with npx react-native run-ios it opens the package manager in TextEdit instead of a Terminal.
When running node_modules/react-native/scripts/launchPackager.command manually from Finder or the Terminal it works just fine. The file extensions is mapped to Terminal and I obviously have correct access rights on the file.
I've also removed node_modules and reinstalled them.
The latest beta of Big Sur seems to avoid this problem. Leaving the question here in case anyone else has the same problem with older betas.