Is the soil typically level and flat up to the base of the tree trunks, or is the soil mounded up around the tree trunks?

If mounded up, I could see that the left-hand side of the deck might raise up while cutting in a counter-clockwise direction around a tree. This might cause the right-hand side of the deck to lower by the height of float in the anti-scalp wheels.

Another thought: have you measured the deck levelness with the wheels completely turned to the left after you have confirmed that the deck is level with the wheels facing straight ahead (not turned)?

I'm curious to know as I have a new X584 and lots of trees!

 

My 2009 x534 had issues with the deck leaning and raising as well. I tried everything I know and never could get a nice level cut unless I lowered the deck wheels pretty much to the point of riding on the ground. That's the only reason I sold it as it was like brand new with 50 hrs. The older engine imo is far superior to what they use today. You and myself are far from the only x534 owners that have complained about this very problem.

The x584 has a revised 4ws system. I have no clue if this was addressed or not.

 

I have an x534, and have this issue, around some trees. Chances are, the ground is a tad unlevel. I'm not sure how you'd expect a level cut, mowing an unlevel surface. You're cut will be parallel to the ground's slope, which is probably not exactly to what you'd consider the flatness of the surface of your entire yard. The only way you'll solve this is putting the wheels low, which doesn't seem like the best idea, or recommended. The bigger deck makes the problem more noticeable. I had similar issues around some trees with an x300 with a 42" deck, and an x530 with a 54" deck. The smaller deck made the scalping less visible, because you aren't trying to span as big of an area/slope.

The faster you're driving, and the harder you turn will also exaggerate scalping.

 

I'm aware of the ideas you speak of regarding slopes. That makes sense, but I can spin in a circle on flat land and this will happen.

I'll do additional testing to try and make sure all other things are consistent and report back.

My x534 is a 2006.

 

My X590 does the same thing. Going downhill going around my edging blocks which is flat side to side it hardly cuts anything on the left inside. Always have to take my Stihl trimmer around the blocks to level it out. Pretty annoying. But don't know there is a fix for it.

 

You might want to check your wheels for vertical when turned. I believe they may change so the wheels don't tear up the grass. If one changes and the other one doesn't, it would tip the mower slightly. Speed will also matter, since the center of gravity will also cause the tractor to tip (right when turning left).

If it does it around all trees and when just making a turn in the middle of the yard, it has to do with the tractor. I noticed the same thing more on my 48" than I did with my 42" when going around trees. Did you watch to see if the anti-scalping wheels were touching near the tree? That would lift that side and lower the side away from the tree.