Thanks Henrik,
I'll explain a bit further: I can load POSCNTH and POSCNTL, and they show up as correctly loaded, but as soon as the encoder moves, it jumps back to 5535 and rolls to 0 from there.
I can change MAXCNT, but that doesn't put it in the middle of the count range and avoid the rollover.

The reason I asked about MAXCNT value of 1527h is that it is mentioned in the datasheet, on page 173, note 5, and I thought it is a strange number.

Like I said, there are obviously ways around this, I'm just trying to understand it better.

Thanks
Mark