Shoes look OK slight scuffing on bottom plate no slop in spherical thing but maybe too much clearance between separator and piston slipper perhaps something out of balance looks to be chattering until it cuts slippers off
Unless it springs from cartridge that preloads bronze which in turn preloads slipper thrust onto plate therefore oil leakage at slipper bottom forcing up when intake and chattering. I reckon that what it may be. I gotta sleep so check back later
That retainer pushes against tha swash plate by the sphere on the piston barrel? The problem could be not enough axial force to retaining ring.
Yep! And I don’t have it here but look and see if the too thick of a gasket under that three bolt bearing holding end cap might be a problem, plus aftermarket cartridge/ barrel/ cylinder block can be too short.