Quick answer: Godot 4 .NET debugger silently detaching after running scenes back-to-back? AppDomain reloads invalidate the debugger connection - restart the editor or use the external debugger profile.

Run scene, debug fine. Stop, edit, run again. Breakpoints turn hollow; the debugger isn't actually attached.

Use Rider/VS external debugger

External debuggers reconnect on each Godot run because they're attaching at process-start time. The integrated VS Code path is fragile across AppDomain reloads.

Or restart editor between sessions

Heavy-handed; works. Editor restart resets the AppDomain entirely.

Verify breakpoint state

VS Code's UI doesn't reliably indicate detach. Hover the breakpoint dot - 'not bound' = detached.

“Editor-integrated .NET debugging in Godot is in active development. External tooling is more reliable.”

Configure both Rider/VS and VS Code paths in your project's launch.json. Switch when one frustrates you; the other typically works.