I'm also experiencing this. Running Xcode betas.

I have ended up adding a scheme to my project to build and run without(!) debugging as a halfway work around. Most of my apps will continue (Control-Command-Y has never been so helpful), but one of my apps fails to run if its launch is interrupted this way—so no debug for that one.

I'm getting this all over the place with building and running my apps on Xcode 12.2 Beta 3 on macOS 11 Beta 10. Hope there's a work around or fix. Also continuing doesn't always work for me.