Install overwrites partition tables?

Hi all,

I have a SS5 with two internal (ID's 1 and 3) and one external disk (ID 4).
I've installed OpenBSD on the two internal disks, then proceeded to
install Aurora on the external one. I chose Custom Install and partitioned
using fdisk, taking great care to only touch the third drive (sd2).
The install finished without problems, but upon reboot, the partition
tables of the two internal drives seem to have been altered as well -
OpenBSD was no longer able to find its partitions. How can this be
even though I didn't touch those drives? Does the installer do
something out of itself without asking? Or have I missed something?

Cheerio,

Thomas
-- 
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                Thomas Ribbrock    http://www.ribbrock.org 
  "You have to live on the edge of reality - to make your dreams come true!"