samba - Nov 2010 - File change on files > 4095 Bytes

I'm using Samba 3.4.7 on Ubuntu 10.04 server.

When i'm saving a file>4095 Bytes on one of my samba shares the editor
pops up again and says the file has changed and asks my if to load it again.
When the file is less than 4096 Bytes everything is ok.

I didn't have this effect on the ubuntu 8.04 server i've used previously
with the same smb.conf.

Any ideas?

Jens