samba share shows many hidden files like ".directory.lock.?????.test"

I just noticed that I find lots of hidden files named “.directory.lock.???.test” across my samba-shared file system. The questionmarks stand here for some random alpha-numeric patterm.
My questions are:

  • Which application might have created them?
  • Is it save to delete those ?
    With e.g. “find . -type f -name “.directory.lock.???.test” -exec rm -f {} ;”

Am I the only one to see such files appeare on my disk?