Didn't fix it. Still have the stutter, still have the crash after second death with the same err.log output.
I slapped it onto my work laptop which has an AMD GPU + i7. The post-death stutter doesn't happen! However, the crash after second death still does, with a slightly different error log:
Exception in thread "LWJGL Application" java.lang.NullPointerException
at com.solarlune.gearend.objects.interactables.Treadmill.main(Treadmill.java:49)
at com.nilunder.bdx.Scene.runObjectLogic(Scene.java:865)
at com.nilunder.bdx.Scene.update(Scene.java:923)
at com.nilunder.bdx.Bdx.main(Bdx.java:338)
at com.solarlune.gearend.BdxApp.render(BdxApp.java:44)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:223)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:124)