Instance of IceExternalJob did not understand #debug

[labordep]

Bug description During loading a GitHub project an error appears when I click to the red cross button in the loading bar:

I'm with a limited and not stable connexion, that's why I think this is not releated to the project because I succeed to load in an other way.

This problem appears after this error:

Version information:

• OS: Windows 10 Pro
• Version VM: 10.3.0.0
• Pharo-12.0.0+SNAPSHOT.build.1521