iPhone XR notification sounds

Got a used XR recently. I erased all contents and settings. Loaded my settings, from iCloud and everything except New Mail sound works properly. I use Gmail for my emails. I set the notification sound to Bamboo but some unknown sound plays. It is not even a sound in the library. I have turned the phone on and off. I have made sure all the sound switches are turned on.

Nothing I have done has changed the sound. Help, please.