A minor glitch in search?

When I set up the search as below, MS .docx documents are also shown in the results. Am I setting the predicates incorrectly or it’s a minor glitch?

Thanks

Thanks for the report! I reproduced this here.
@cgrunenberg will have to look into this.
Thanks for your patience and understanding.

The rich text kind is a generic kind for all file-formats compatible to the text engine of macOS, actually since version 1. Just like the plain text kind includes many different file types. You could use the extension condition to retrieve only RTF and/or RTFD.

got it. Thanks