ReferenceError: Can't find variable: capturedPromise when invoking an extension command from another extension

I’ve been playing around with extensions to see what they’re capable of accomplishing.

I’d read a thread someone else started where they asked if it was possible for extensions to share state and the answer was that they could not, but that they could invoke each other’s commands.

I’ve sought out to do just this: I generated 2 extensions, registered a command in one and then tried to invoke it from the other.

This appears to work, but results in an error in the console:

Extension encountered an uncaught exception:
Error: ReferenceError: Can't find variable: capturedPromise

I don’t have capturedPromise anywhere in either extension so I can only assume this is from within Nova itself.