Try and change the following in your Configuration.h file:
And see if that fixes your problem.
// ENCODER SETTINGS // // This option overrides the default number of encoder pulses needed to // produce one step. Should be increased for high-resolution encoders. #define ENCODER_PULSES_PER_STEP 1 // Use this option to override the number of step signals required to // move between next/prev menu items. #define ENCODER_STEPS_PER_MENU_ITEM 5
And see if that fixes your problem.