GarageBand adding an extra 10 seconds

Hi all,

One of my new songs recorded in GarageBand always adds an extra ten seconds at the end when I share it to Music or export it to disk. It's a short song - 2 minutes 19 seconds - and when I play it on music it is always 2 minutes 29 seconds, including 10 seconds of dead air at the end. I have ensured that the end marker is at the right place, as I always do, but that makes no difference. I don't have the metronome on. It makes no difference whether I share it compressed or uncompressed. I do not have this problem with any other song. Any suggestions please?