Sometimes wrong language after update 2.0.22a

[EIF]

Recently I updated to virtuemart 2.0.22a with joomla 2.5.11.
My website is running in Dutch language, but after update there are many fields displaying in English. The language file is available and the fields are translated. But virtuemart isn't always using this dutch language file, but is using the English one.  Website is displaying both English and Dutch now.
Is this a bug, or do I need to change something?