wierd play error

[dsssssssss9]

Hi

when i use the example code & if i have the serial monitor open i get the following ....

the myMP3.play() command plays the 1st part of the previous mp3 followed by 1st part of the current mp3 then the full current mp3...

https://user-images.githubusercontent.com/30810847/156258855-9aae3de0-99b8-4971-bbda-5c8f932f4308.mp4

if the serial monitor is NOT open this does not happen

Any clues as to what may be happening would be appreciated!

Arduino UNO Arduino 1.8.15 DFPlayer Fast v1.2.4