For set_z_fade_height use set_bed_leveling_enabled

Marlin/src/feature/bedlevel/bedlevel.cpp

 
   void set_z_fade_height(const float zfh, const bool do_report/*=true*/) {
 
-    if (planner.z_fade_height == zfh) return; // do nothing if no change
+    if (planner.z_fade_height == zfh) return;
 
-    const bool level_active = planner.leveling_active;
-
-    #if ENABLED(AUTO_BED_LEVELING_UBL)
-      if (level_active) set_bed_leveling_enabled(false);  // turn off before changing fade height for proper apply/unapply leveling to maintain current_position
-    #endif
+    const bool leveling_was_active = planner.leveling_active;
+    set_bed_leveling_enabled(false);
 
     planner.set_z_fade_height(zfh);
 
-    if (level_active) {
+    if (leveling_was_active) {
       const float oldpos[] = { current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS] };
-      #if ENABLED(AUTO_BED_LEVELING_UBL)
-        set_bed_leveling_enabled(true);  // turn back on after changing fade height
-      #else
-        set_current_from_steppers_for_axis(
-          #if ABL_PLANAR
-            ALL_AXES
-          #else
-            Z_AXIS
-          #endif
-        );
-        SYNC_PLAN_POSITION_KINEMATIC();
-      #endif
+      set_bed_leveling_enabled(true);
       if (do_report && memcmp(oldpos, current_position, sizeof(oldpos)))
         report_current_position();
     }

Marlin/src/gcode/calibrate/G28.cpp

   // Disable the leveling matrix before homing
   #if HAS_LEVELING
     #if ENABLED(RESTORE_LEVELING_AFTER_G28)
-      const bool leveling_state_at_entry = planner.leveling_active;
+      const bool leveling_was_active = planner.leveling_active;
     #endif
     set_bed_leveling_enabled(false);
   #endif
   #endif
 
   #if ENABLED(RESTORE_LEVELING_AFTER_G28)
-    set_bed_leveling_enabled(leveling_state_at_entry);
+    set_bed_leveling_enabled(leveling_was_active);
   #endif
 
   clean_up_after_endstop_or_probe_move();