I'm moving the conversation from another issue to it's own ticket at it turned out to not be related to the original issue.

First comment #1708 (comment) by @ctotheameron

This issue is an extension of #1702 which was partially fixed in #1703.

The DataMatcher type is used to type the optional body argument of "method" methods on Scopes (.post, .put, etc.) as well as typing the argument passed to Interceptor.query.

Of note is that arrays are valid types to pass .post, but it is not valid for .query.