managing categories error

[2cool]

Have some issues while managing categories and subcategories.
Setting categories to subcategories or adding new subcategories are not always saved.
Read about language issues causing this...

I see this message in vm error:
4 vmdebug COM_VIRTUEMART_MISSING_FLAG Var1:
en
Var2:
English (United Kingdom)
5 vmdebug Active vendor 0 1

What's the best way to fix this. Joomla 3.8.11 and VirtueMart 3.2.14

Thanks,
Pas