This was raised and answered on the GitHub
Thanks for your feedback regarding the scope format. While we strive to follow RFCs as closely as possible, occasionally deviations do occur. Changing our scope value from an array to a space-separated string would be a significant breaking change for existing applications. Making this change to be inline with the RFC does not outweigh the disruption it will cause, so we will not be updating the format in the current implementation. This may be something to consider in a future implementation, but as there is no action at this time, this issue will be closed.