MediaFileIndexer issue with Serviio 1.5.1 on linux-Zyxel NAS

I am getting the following warning, after copying video file to Serviio watched directory:

File '/mnt/HD_a2/photo/videotest/fringe.512.hdtv-lol.mp4' cannot be read, probably due to access rights

The problem arrives only if the video file was copied preserving file attributes:

  Code:

cp -a /mnt/HD_a2/photo/fringe.512.hdtv-lol.mp4 /mnt/HD_a2/photo/videotest

If the file is copied other way, without preserving file attributes (cp instead cp -a) or using Midnight Commander or via SMB/CIFS, it is recognised and added to library. It can't be permissions issue (file has the same 644 permissions before and after copying in any event), because file is readable by all users.

What can be this problem related? Is that a scanner bug?
Can someone do the same test and confirm or deny this issue?

Attached debug.log to this post. /mnt/HD_a2/photo/videotest - directory is watched by Serviio.
Steps to reproduce:

  Code:

cp -a /mnt/HD_a2/photo/fringe.512.hdtv-lol.mp4 /mnt/HD_a2/photo/videotest

  Code:

cp -a /mnt/HD_a2/photo/fringe.513.hdtv-lol.mp4 /mnt/HD_a2/photo/videotest

Permissions:

ls -la /mnt/HD_a2/photo/videotest/fringe*
-rw-r--r-- 1 root root 270M Jan 19 2013 /mnt/HD_a2/photo/videotest/fringe.512.hdtv-lol.mp4
-rw-r--r-- 1 root root 265M Jan 19 2013 /mnt/HD_a2/photo/videotest/fringe.513.hdtv-lol.mp4

[zip]

I'm not sure if this is even possible, but might be that the inotify even has been triggered but the file is not actually on the filesystem yet?