Sound plays when it shouldn't

I have put music in a movieclip and put the movieclip in frame 3.(1 single frame)
The music in the movieclip is not set to loop and repeats 0 times.

When testing the movie the playhead should pass frame 3 only once. So one would think the music would play once and that’s it.
But here’s the thing. The movie is set to stop() at frame 5.
On frame 5 there’s a button with which one can gotoAndStop() to frame 10.
On frame 10 there’s a button again to gotoAndStop() to frame 5.
So once in frame 5 one should never pass frame 3 right? So technically the music should play once.

However when one clicks on the button on frame 5 to go to frame 10 and then again presses the button on frame 10 to go to frame 5, then the music starts again.

I have tried to give the sound frames a sync type of event, start and stream, with every type the same thing happens. Once the music has stopped playing and one clicks the buttons to go back and forth between
frame 5 and 10 then the music starts playing again which is in a movieclip which is on 1 single frame, namely frame 3.

I’m puzzled as to how this is possible. I want the music only to play once and not again and again when switching between frames 5 and 10.
Does anyone happen to know why this happens and what the solution could be?