Manufacturer Sef Alias changes itself

[chrlar]

I don't know why, but the Manufacturer Sef Alias keeps changing to a date-like number... And I don't know how to fix it.

We would like for the alias to be the manufacturers name, like just michelin or michelin-produsent, something simple.
But after some time, a day or so, it changes to 2013-03-14-06-15-2810968296 and similar numbers/dates...

Why??

We have a module with some of the manufacturers logos, an with links to the manufacturer page. And when this change happens to the alias, our links stop working, an we have to rename the aliases manually over and over again...

It looks better with a link like
http://www.kollevold.no/component/virtuemart/produsenter/omp-produsent?Itemid=0
than
http://www.kollevold.no/component/virtuemart/produsenter/2013-03-14-06-15-281987059388?Itemid=0
which should have been
http://www.kollevold.no/component/virtuemart/produsenter/michelin-produsent?Itemid=0

And I'm getting fed up... Why do they change themselves??

(Joomla 2.5.9 and VM 2.0.18a)

[chrlar]

Since I wrote this first message, most of the aliases has renamed themselves twice (!)

Please help!!!