Has anyone else experienced a random fire alarm sound coming from there iPhone?

iOS 11.1.1 here. Same thing. Not sure why this happened. This is what the now playing said: http://1898061103.rsc.cdn77.org/static/e766f2c81fd9a913e70afa9bae011bf/mediastat ic/bb.mp3

What is this address? Where did it come from?

Has this been answered?

Is it very possible that you have Government Alerts activated on the iPhone? Check Settings>Notifications>Government Alerts. If there is an emergency alert such as a flood warning, severe weather warning, or an Amber warning, you will get those, and they sound whether the device is on mute or not, and the volume is set to high and cannot be changed.

This happened to me too just now. Was at work with my phone on my desk and it started going off. NOT an Amber alert, I know what that sounds like. But it sounded just like a fire alarm and me, nor my colleagues could tell where it was coming from. I put my phone in my pocket and was walking around trying to find the source, but I thought the entire building alarm was going off. Until someone told me that the sound was following me, and I looked at my phone. Some URL was scrolling across the screen as if it were playing a song. I pressed pause and the noise stopped and the url disappeared.

Does anyone have any thoughts on the cause of this?

It's not Reddit that's the issue. It's the third party apps. So, just accessing Reddit from your browser wouldn't seem to be a problem.

Also, the number of instances were very small.

Have you updated to iOS 10.3.2?

I'd suggest that it might be an Emergency (not Amber) Alert but, in all likelihood, every phone in the building would have been going off if that were the case. If I recall, the Emergency Alert sound is different than the Amber and much scarier.

Well, if it doesn't happen again, I'd write it off to cosmic rays and not worry too much. If it keeps happening, I'd consider restoring the device to factory state, syncing your mail, contacts and calendar. Then, add your third party apps back a couple at a time and test for a long enough to determine if they're the problem. That would help you isolate which third party app was the issue. But, it's a time consuming and annoying process, not worth the trouble for a rare bug.

Do you have any third party apps for accessing Reddit? I've found some reference to two different ones causing this problem, Narwal and BaconReader.

No I don't have any of those. I have never been on reddit on my phone either as far as I know.

No I dont have any of the apps. I updated the most recent OS yesterday.