BLE Advertising stops when connected

I changed now back to advertise without casting to string but than i only get integer temperature values...

setInterval(function() {
  
  NRF.setAdvertising({
    0x2a01 : [E.getTemperature()],
    0x2a19 : [Puck.getBatteryPercentage()]  
  });
}, 3000);

advertises:

/ble/advertise/c1:76:57:2e:39:b7/2a01 : msg.payload : Object
Objectraw
0: 0x15