unusual TR error: keyword is missing, keyword is unexpected

['John Clements' via dev-redirect]

I haven’t taken the time to try to narrow this down yet, but code that works on my work machine signals this peculiar error on my home machine (I believe this is a more recent build):

- Type Checker: Missing keyword argument #:To in: (send-single-email POSTMARK-API-KEY #:From from #:To to #:Subject subject #:Body body)
. Type Checker: Unexpected keyword argument #:To in: (send-single-email POSTMARK-API-KEY #:From from #:To to #:Subject subject #:Body body)

Apologies if this is already fixed.

John