This is my theory, and valid only if the top and bottom halves do NOT make hard contact with each other.
When you assembled the whole shebang, you had slight mis-alignment of the rings in the bases. You tightened the screws what you considered a sensible torque so as not to damage the scope tube.
THEN, after a period of shooting and recoil, the rings aligned themselves in the bases and you now have "slop". (a technical word for too much clearance)
Hopefully proper alignment and re-torquing will solve the problem. I hate the thought that either Leupold rings, or Sightron scope tubes could be incorrect in diameter. jd
+1
alignment bar and lapping rings is a worthwhile endeavor. you would be surprised how many times i have had people who needed lots of windage adjustment sighting in a rifle. Alignment bars will identify the problem and proper lapping will fix it. that is unless you have a truely messed up set of rings. then at least you have identified the.problem.