Hi Rohit,
I ran by my side and it works.
Please see my process below. What is the process that you are following?
1. I program the bootloader_otap for the QN9080.

2. I program the QN9080 qn908xcdk_wireless_examples_bluetooth_otap_client_att_bm example.
3. Select the s19 file that I created from the MCUxpresso.

4. Update the firmware

5. Transfer successfully

6. The new firmware starts the adv after I press the button.
Regards,
Mario