Maverick corrupts files on samba network shares

my installtion of Ubuntu 10.10 64Bit Desktop Edition has one severe Problem when using Samba Shares:

When I edit files (i.e. using gedit) that lie on the Network share and I happen to remove some content (making the file smaller in size) and then save the file, The file get's corrupted - the size remains the same as it was before, and when I reopen the file has trailing garbage.

This also happens if I try to overwrite a file with one that is smaller, the result is garbage.

What can I do against it ?

Details:
Always reproductible.
Happens with smb shares that lie on Windows Machines as well as with an Ubuntu Hardy Server's share.
Only my Maverick Machine produces this corruption.
Copying new files works without problems.
Increasing file size also works.
Just when I try to decrease the file size corruption occurs.

The only workaround I have so far is to delete the file on the share, and then copy the new file - quite annoying.

Any Ideas, tips, hint welcome.