nepomuk cleanup trashing addressbook ?

so, I just experience a very ugly behaviour from kaddressbook (kde 4.4.0):
I have configured simple std.vcf file as a ressource for akonadi, seems to 
work ok, that means, if I add e.g. a new address in kaddressbook, it is 
propagated to std.vcf as expected.
so far, ok.
the problem now is: I seem to loose the newly added addresses randomly from 
time to time, that means, they are no more shown in kaddressbook, nor are they 
in std.vcf !!
I'm under the impression, this happens mostly after I'm forced to clean up 
nepomuk databases via

qdbus org.kde.NepomukServer /nepomukserver org.kde.NepomukServer.quit
rm -r ~/.kde/share/apps/nepomuk
nepomukserver

which happens also randomly (after ~every 3rd or 4th login, where 
akonadiserver refuses to start).

anyone experienced similar things ?

werner