Two strategies to address a stuck buzzer

Marlin/buzzer.h

@@ -124,7 +124,7 @@ class Buzzer {
         this->state.timestamp = millis() + this->state.tone.duration;
         if (this->state.tone.frequency > 0) this->on();
       }
-      else if (millis() >= this->state.timestamp) this->reset();
+      else if (ELAPSED(millis(), this->state.timestamp)) this->reset();
     }
 };
 

Marlin/ultralcd.cpp

@@ -2334,12 +2334,14 @@ void kill_screen(const char* lcd_msg) {
     lcdDrawUpdate = LCDVIEW_CLEAR_CALL_REDRAW;
     next_button_update_ms = millis() + 500;
 
+    // Buzz and wait. The delay is needed for buttons to settle!
     #if ENABLED(LCD_USE_I2C_BUZZER)
       lcd.buzz(LCD_FEEDBACK_FREQUENCY_DURATION_MS, LCD_FEEDBACK_FREQUENCY_HZ);
+      delay(10);
     #elif PIN_EXISTS(BEEPER)
       buzzer.tone(LCD_FEEDBACK_FREQUENCY_DURATION_MS, LCD_FEEDBACK_FREQUENCY_HZ);
+      for (int8_t i = 5; i--;) { buzzer.tick(); delay(2); }
     #endif
-    delay(10); // needed for buttons to settle
   }
 
   /**