"Now all personal music players sold in the EU after February 2013 are expected to have a default sound limit of 85dB. The user can choose to override the limi

"Now all personal music players sold in the EU after February 2013 are expected to have a default sound limit of 85dB. The user can choose to override the limit so that the sound level can be increased up to maximum 100dB. If the user overrides the limit, warnings about the risks must be repeated every 20 hours of listening time. " via http://www.bbc.com/news/health-21294537 http://www.bbc.com/news/health-21294537 The "repeated every 20 hours" would explain why OP was seeing the warning seemingly randomly.