When you reinstalled the bats, did you use a flipper spacer gauge (or a credit card) to set the height of each flipper before re-tightening the clamps?

Baffling . . . there are only so many things that can be wrong with a flipper assembly. Is the flipper chassis on the one that sits low screwed tightly to the underside of the playfield? Is there anything odd at all with the linkage? What about the plunger and sleeve - have you checked those?

Then the assembly must be hanging loose and the bat holding it up. Can you pull the bat upwards from the top?

There is another thread about this problem, or its under the Metallica club thread.

Remove the bushings and inspect them. Also inspect the playfield where they attach. If everything looks okay, swap them and see if the problem moves. I bet it's a bushing issue. Either something is causing one to not mount properly, or one isn't aligning properly due to some kind of manufacturing defect on the bushing.

The screw is a a 10-32 x 7/8" Allen head screw. Some hardware stores carry these in stainless steel, which is preferable. To remove the stripped one, put a box end wrench on the nut, then use vice grips or pliers to loosen the stripped screw. Reuse the split lock washer and lock nut that comes off the stripped screw. Use the alignment holes on the playfield to align the tips of the flippers. If the pawl on that side it badly bent compared to the other side, replace that too.

would have to be 2 different bushing heights, or one is wore down already. it's the only thing it could be. or the bracket mounts for the flippers are bent differently, but I couldn't see that being the case unless there are washers under the backet where it screws into the playfield

Not sure just remember reading it, it has something to do with what is mentioned above ^^^^^

I'd go with CaptainNeo's advice and look there. I had a look at mine and they sit just right and I know they're the same flippers from the same source. So it has to be something like he mentioned. It really is bizarre.
You changed out the bats, and it was still there, so I'm thinking somewhere under the playfield lies the problem. A picture there might help too.

The flipper bats actually rests on the bushings. The next time you have both bats removed, use a metal ruler to measure how far each bushing protrudes above the playfield. If one is higher than the other, either the bushing is worn, your flipper bracket is bent or the mounting is messed up.

Did you remove the bushings? An imperfection on the bushing or playfield could be changing the angle of the flipper shaft. Both should hold the bat perfectly perpendicular to the playfield, but I'm guessing one of yours has a problem. Remove them both and compare them to each other. Also inspect the part of the playfield where they attach. If one screw is high for any reason, that would cause the problem you're seeing. If you're not comfortable going that deep, see if you can find someone in your area to help.

Looking at the bushings, your not going to notice a 1/16" difference in height on them by looking at them. you will notice it on the flipper on the playfield, because you barely have over 1/16" clearance already. Might just have been made wrong, or they had bushings made from somewhere else, and the stats are slightly different. Got mixed in the box with the others. Put a new set of bushings in there from the same source, and should be perfect.