Since 1.1.2000 mutt (mutt-0.95.4us-0) writes wrong year into date line. Example: Date: Mon, 24 Jan 100 07:58:22 +0100 (MET) ^^^ should bei either 00 or 2000 There's a fix available at www.mutt.org for the problem, that still exists in version 1.0.
Fixed in the mutt in Raw Hide.