Having trouble setting the advertising interval for iBeacon

I have taken the example code and added one line to set the advertising interval down to the minimum 20ms. I used nRF Connect to determine the advertising interval and it is still 100ms. No matter how I change the interval, it seems to always be at 100ms. Could I get some guidance on this? I am using Argon.

void setup() {
    iBeacon beacon(1, 2, "9c1b8bdc-5548-4e32-8a78-b9f524131206", -55);

Are you checking the return value?

It is returning 0. I am printing it out with the particle serial monitor.

I am having the same issue. Bug?

Have you tried other advertising intervals whether they work at all?
Have you tried BLE.setAdvertisingParams() alternatively?

I have tried below and above 100ms intervals, no luck there. I have also tried to setting BLE.setAdvertisingParams and passing in BleAdvertisingParams with the interval variable changed, still no luck.

Yup, I tried some alternative ways to set the interval and I can now confirm it really seems to fail to do anything.