Grrr... before submitting I was able to trigger this problem. And then I reverted to 2.6.18-1 and the problem went away. I wanted to test more with 2.6.18-2, but that version is now also stable. I have no rerun the exact same test against 2.6.18-2 several times, and it hasn't failed once. I guess my earlier tests were a fluke. I can no longer confirm this problem. Raf.