Microbit signal data out over bluetooth?

As soon as I posted that, I realised the difference is that the first explicitly sets the service UUID, where as the second snippet does not.

If I update the second snippet to the following, it still seems to give the same error:

NRF.setAdvertising({
  0xFEAA :[
    0x03,  // Length of Service List
    0x03,  // Param: Service List
    0xAA, 0xFE,  // Eddystone ID
    0x13,  // Length of Service Data
    0x16,  // Service Data
    0xAA, 0xFE, // Eddystone ID
    0x10,  // Frame type: URL
    0xF8, // Power
    0x03, // https://
    'g','o','o','.','g','l','/','B','3','J','0','O','c'
  ]
}, {interval:100});