Originally Posted by starchile
No, I don't have anything blacklisted (yet)...but also no, it doesn't match my notification sound.
The NFC notification noise is different than other ones, and I don't think it can be changed. See if having it off keeps the noise from happening. An even better indication that it was NFC is if you keep your phone anywhere near anything that has NFC (some credit cards do now). The sound could be from your phone trying (and failing since those are encrypted) to connect to the NFC in a credit card. But keep us in the loop if the noise keeps happening even with NFC off.