I had exactly similar issue/perception. Also felt like it ‘wallowed’ sometimes although the rebound I thought did make a difference. Propedal hardly any difference. Hard to explain exactly – but never felt quite right. Also had to run with a pretty high shock pressure to get the right level of sag. Kept tweaking the pressures and found it very sensitive to this. Got it as best I could, but ran next to no rebound where it eventually felt ok – but nevertheless pretty was always a little ‘chattery’ and never as plush as I wanted.
Prior to buying it – I had a demo on it with a rockshox aircan(can’t remember which one) but I can’t recall having the same issues – obviously or I possibly wouldn’t have bought it!
Eventually put a coil on it (CCDB) and feels really good now and happy – but obviously there is a weight penalty and not insignificant cost to consider!