visitorid not showing correctly inside visitorid column (no replies)

hello,

I am using piwik version 2.4.1
after using the following GET command:

http://xxxx.url.tld/piwik.php?action_name=View%20settings&url=http://mobileapp.piwik.org/window/settings&idsite=1001&
rand=351459&h=18&m=13&s=3%20&rec=1&apiv=1&urlref=http://iphone.mobileapp.piwik.org&_id=0123456789ABCDEF&
_idvc=19&res=320×480

the idVisitor which i can see in debug is: "#Eg‰«Íï"
while I am expecting to receive "0123456789ABCDEF"

in addition, whenever i decode the blob item inside mysql i receive a different id.

is this a known issue for older versions ?

Cheers,
Nadav Stern