I can’t exactly pin down when this behavior started, but it has happened in the last few days.
When I load the playground in Chrome (no changes to chrome recently), I get this error.
Uncaught TypeError: this.parent.monacoCreator.addOnMonacoLoadedCallback is not a function
I can still load the playground on Safari.
Any ideas? I did update to OS X Catalina in the last week. May be related, not sure.