MYO cards only playing partial tracks

I have created a playlist of nursery rhymes for my son, there are 7 tracks. They play fine at the start then cut out for a few seconds then play again. This only happens with tracks over 1 minute. Do I need to keep tracks below 1 minute? If so, how am I meant to record stories etc? All of the normal cards I have, the tracks are all over 1 minute so I'm a bit miffed, really 😕