Qt Incorrectly Reinterprets Fontconfig Preferences Leading to Inconsistent Font Rendering

Qt seems to re-call fontconfig with the preferred font obtained from fontconfig as the pattern, using the final obtained font sequence, which leads to an inconsistency with the result of fc-match -s. Specifically, when a monospaced font (containing only CJK characters) is configured as the preferred font for the sans-serif family, Qt applications incorrectly render all text using monospaced fonts, even for non-CJK characters.

Steps to Reproduce:

1. Configure fontconfig to use a monospaced font containing only CJK characters as the preferred font for the sans-serif family.
2. Run an application that uses Qt's font handling mechanisms.
3. Observe the font used in the Qt application for both CJK and non-CJK characters.

Expected Behavior:

Monospaced fonts should be applied only to CJK characters, while other characters should use a fallback sans-serif font as per the fontconfig configuration.

Actual Behavior:

All characters, including non-CJK ones, are rendered using monospaced fonts.