just going to add this as its something simple you can try
remove your bucket, and see if it does the same thing
I know on some older skid steers, if you don;t have a correct bucket(no there NOT all the same)
but I have sen where if the bucket was say places on a small pile of dirt, and shut off a while, the system would bleed down, and raise the front wheels off the ground
due to the bunch not being able to return fully down
( same is if if you had a bucket that doesnl;t allow full down),
the weight of the lift arms will be enough to raise the front wheels
so, if you remove buck, and park, does it STILL lift the front wheels!???
easy enough to try and will help eliminate something!