CD error scan: only errors at high speed. Copy protection?

An undamaged, out-of-the-box CDDA has 31 C1 errors and 0 C2 in total at ×8 CLV reading speed.

If I go to ×24 CAV, there is a peak at 3K errors for C1 and over 700 for C2 at 50 minutes. I will upload screnshots tomorrow.

But the rest of the CD is undamaged. Same low error rate.

If I go to ×40 CAV, the C2 peak reaches 160K. C1 reaches 220K.

The same effect happens to all drives, just different error counts.

However, on high speed audio extraction, there are no acoustic errors perceivable!

How can this be explained? Copy protection mechanism? How does it work?