hdrdefault color is not honored after a search matched by a header that hasn't been colored yet

The hdrdefault color is not honored after a search matched by a header that hasn't been colored yet, e.g. not displayed yet. To reproduce:

1. Open a mailbox with a muttrc having a line like color hdrdefault magenta black, e.g. with header-search-color.mbox and header-search-color.muttrc
2. Type h (display-toggle-weed).
3. Optionally display the next few lines and go backward.
4. Search for some text that is matched by a header that hasn't been displayed yet and that isn't the first not-displayed header, i.e. with /150 on the example.

The headers appear in the normal color instead of the hdrdefault one. Ditto when going backward. The correctly colored headers are the first header that had not been displayed yet and those before it.

This bug is still present in master and was already present in Mutt 1.10.1 (in Debian 10 buster).