This is not an issue, when we detect a mobile device, we use the default HTML5 player, not the mediaelement js player.
MEJS is a great player, but it is not 100% on mobile devices, specifically phones bloated with software. Using the native HTML5 player passes on the performance issues to the phone itself. In 1-2 years when everyone has dual/quad core processors in their phones hopefully this will not be an issue, but it is still today.