Empty files in home directory - Opendirectoryd

Dear Sirs,

One of my colleagues reported some empty files appeared in the home directory of his computer. Their names have not conventional chars. I attach an image with the name of the files.

All the files have the same creation date. We erased the files the first time.

The event happened again. The same files appeared. Reading the log files, we found this message in opendirectoryd.log just at the time the files were created (the first and the second time):

2015-07-06 12:03:38.422868 PET - 969.3123 - Client: bash, UID: 501, EUID: 501, GID: 20, EGID: 20

2015-07-06 12:03:38.422868 PET - 969.3123, Module: SystemCache - no record type and/or values to query

The problem appeared in a Intel IMac with Mountain Lion, 1 Tb memory. Even this, the computer is working well, but we would like to know the reason of this event.