Some tracks have these many minutes of silence at the end such as those by Beck's albums Odelay and Mellow Gold. Gapless playback won't advance to the next track during this "middle of the track" silence.
Hi, a similar idea has also been suggested here:
It's slightly different in its suggestion, but if implemented, it would allow you to manually select to skip over particular parts of the track. While it's been marked 'Not Right Now', Spotify staff periodically reviews these ideas and may choose to implement it in the future. Add your kudos and comments there please!