[REQUIRED] Environment info

firebase-tools:
13.0.1

Platform:
Ubuntu

[REQUIRED] Test case

Start a Firebase emulator by running firebase emulators:start

[REQUIRED] Steps to reproduce

Same as above

[REQUIRED] Expected behavior

Firebase emulator starts without any error.

[REQUIRED] Actual behavior

Firebase emulator starts, displaying false warning about an emulator instance already running, and then crashed showing the message: An unexpected error has occured.

firebase-debug.log