Does it still happen now, in normal use?
I got a reply from Optiarc, but no useful information. They suggested it may be due to bad disc conditions (despite me already telling them the discs are pristine, show good scan results, and that reinsertion [and sometimes DriveSpeed] resets the speed to 100%).
They even tried educating me about how CAV reads slower on the inside…
Now I’m waiting for another reply (hopefully I’ve passed the barrier of canned answers).
And I’m surprised no one else noticed this? It smells like a firmware bug, so it’d be rather odd if it turns out to be a unit-specific problem.