4g vs Wifi discrepency

My app uses the music player start and stop times to play only a sample of each song. On my mobile web app version i’m having a slight problem. When its on wifi it works as expected, when i switch off my wifi to test on 4g, the rest of the app works perfectly but the start and stop times get ignored. It just starts the song from the beginning and plays all the way through. Does anybody have any idea why this might be happening?
(Also this only seems to be happening on android and not Iphone)