setAdvertising: Multiple packets Issue

Nic did say he'd tried the absolute latest build as of his post...

You don't have the version of your code that worked before when you posted everything was fine do you?

You'd expect that:

NRF.setAdvertising([require("ble_ibeacon").get(...)],
   {manufacturer: 0x0590, manufacturerData:[...]});

Would only do iBeacon, because require("ble_ibeacon").get is supplying binary data which can't be modified to include the manufacturer data. The second option should work though - I don't have a device here to test with so I'm not sure what to suggest, but maybe see if adding more advertising packet types changes things - and try something else to debug it, like nRF connect on a phone