Hello everyone, I'm writing a piece for acoustic guitar and flute, but something strange happens with the flute part (Flute solo KS). It sounds all right until bar 12, when suddenly the volume of the flute goes down considerably. I also tried to do it all over again, but at bar 12 the flute score has this strange loss of volume. In order not to lose the idea I eventually had to transcribe it all on Guitar Pro. Do you have any tips or suggestions for this problem?

Finale 25.5 Windows 10 GIFF GPO5