messages silently ignored in mbox mailbox when the "From " line contains additional information

In an mbox mailbox, when the "From " line contains more than the e-mail address and the date (e.g. information coming from the "From:" header), Mutt silently ignores the message.

The issue is that there were no specifications for the mbox format in the past (and even nowadays there are still different assumptions about it). And I have an old mbox file where additional information has been kept in the "From " line, and it took me some time to discover that Mutt silently ignored the messages: I noticed the ignored messages only after doing an external grep. This is a major issue as one may not notice that data are missing (as this initially happened to me).

Example:

From u1@a.invalid Wed May 29 12:21:43 1996
From: u1@a.invalid
Subject: msg 1
Content-Length: 6
Lines: 1

msg 1

From u2@a.invalid (comment) Sat Jul 27 03:26:47 1996
From: u2@a.invalid
Subject: msg 2 - not shown in Mutt 2.2.9
Content-Length: 32
Lines: 1

msg 2 - not shown in Mutt 2.2.9

From u3 <u3@a.invalid> Mon Aug 12 14:43:33 1996
From: u3@a.invalid
Subject: msg 3 - not shown either
Content-Length: 25
Lines: 1

msg 3 - not shown either

also attached: ex1996.mbox

Mutt should support relaxed "From " lines, e.g. just requiring that it ends with a date (there could possibly be a configurable regexp for that).