@Boots33 said:

I have made a change to the Sketch. I was saving my data to the same EEPROM positions that MySensors use for their data. So i have now moved well away from that area.

Are you're sure, that 514 and 515 are vaild values? API documentation states, that pos parameter in saveState/loadState must be between 0 and 255. AFAIK data stored by saveState are written into a separate section of EEPROM, which doesn't interfere with MySensors own configuration data.