diff --git a/Marlin/Marlin.h b/Marlin/Marlin.h
index 961917cd9..a161682c5 100644
--- a/Marlin/Marlin.h
+++ b/Marlin/Marlin.h
@@ -50,7 +50,7 @@ void idle(
   #endif
 );
 
-void manage_inactivity(bool ignore_stepper_queue = false);
+void manage_inactivity(const bool ignore_stepper_queue=false);
 
 extern const char axis_codes[XYZE];
 
diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index 72560c608..e965274af 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -13616,7 +13616,7 @@ void disable_all_steppers() {
  *  - Check if cooling fan needs to be switched on
  *  - Check if an idle but hot extruder needs filament extruded (EXTRUDER_RUNOUT_PREVENT)
  */
-void manage_inactivity(bool ignore_stepper_queue/*=false*/) {
+void manage_inactivity(const bool ignore_stepper_queue/*=false*/) {
 
   #if ENABLED(FILAMENT_RUNOUT_SENSOR)
     runout.run();