TX LED stay ON after the Serial Monitor is closed

Hello :)

I don't know if it's a bug, but in my current program I have a Serial.print that prints some data every seconds in the Serial Monitor. So the TX LED is blinking every seconds, until now everything is normal.

But if I close the Serial Monitor, the LED continue blinking for approx 93 seconds, and then stay ON. After a press of the Reset button, the LED is still ON.

Only when I unplug the power (from USB), and plug it back, the LED stay OFF as it should. When I reopen the Serial Monitor, the LED starts blinking every seconds again, as should, and the problem always happen like 93 seconds after I close the Serial Monitor.

Any idea why? Should I check if Serial.available() before the Serial.print? :astonished:

just cause you close the serial monitor does not mean your arduino stops sending bytes which is being stored in a buffer somewhere on your computer or USB interface (if using usb to serial)