Level Bed Corners is a sub-menu

Marlin/src/lcd/menu/menu_motion.cpp

   #endif
 
   #if ENABLED(LEVEL_BED_CORNERS) && DISABLED(LCD_BED_LEVELING)
-    ACTION_ITEM(MSG_LEVEL_CORNERS, _lcd_level_bed_corners);
+    SUBMENU(MSG_LEVEL_CORNERS, _lcd_level_bed_corners);
   #endif
 
   #if ENABLED(Z_MIN_PROBE_REPEATABILITY_TEST)