I have a small amount of play (1/8”) with my axle slots. I always set the bike on the ground and run a strap through the wheel and strap it to the rear engine mount area so that things don’t shift when I torque the axle and I imagine it won’t shift when I’m riding. I noticed one day that my axle locators weren’t butted against the adjusters. So now I always check that before putting the tools away. You might not have two axle plates that are perfectly parallel and the axle might be shifting on one side as it tightens up.

I have a small amount of play (1/8”) with my axle slots. I always set the bike on the ground and run a strap through the wheel and strap it to the rear engine mount area so that things don’t shift when I torque the axle and I imagine it won’t shift when I’m riding. I noticed one day that my axle locators weren’t butted against the adjusters. So now I always check that before putting the tools away. You might not have two axle plates that are perfectly parallel and the axle might be shifting on one side as it tightens up.