Strange date format in git-send-email

Dear list,

My email is sorted by date and a number of email-patches list the date format 
as unknown (in kmail, that is).

When checking the headers of these mails I see the following pattern:

Date: mer, 05 jui 2006 00:36:08 +0200
X-Mailer: git-send-email 1.4.1

Date: wto, 20 cze 2006 17:59:19 +0200
X-Mailer: git-send-email 1.3.0

Date: Tue, Mar 14 12:12:35 2006 -0500
User-Agent: send_patch 0.1

Date: Tue Feb 7 18:21:02 2006 +0100


Some of these are quite old, and it has been sometime since I last noticed it 
(I actually thought it was fixed). But today I received another patch-email 
from the list ([PATCH] Beautifulise git-show output), which showed the same 
problem.

Is this my problem (or kmail), or is there something funny with 
git-send-email? I just don't git it.

If you need more info, just holler.

Kind regards,
Martijn
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Actually, did actually notice actually how many times non-native English 
speaker actually use actually?