When "Differential Revision:" is preceded by a newline or in certain other cases it isn't detected as a field. This means that commits like https://reviews.freebsd.org/rD46733 and https://reviews.freebsd.org/D2116 are not getting recognized and auto-closed. However, commits such as https://reviews.freebsd.org/D2660 are.
When detecting fields, the parser should be more lenient about whitespace and the location of the exact text "Differential Revision:"