Could you help me diagnose this noise?

Hey,

So I've had my 8 for about 9 months now, and occasionally it makes a sort of clunking noise.

Here is what I know:

It happens sporadically. I don't think I've ever heard it when the engine was cold, but it won't necessarily happen when it's warm either. No check engine, no noticeable loss of power, no smoke, or any other cause for concern. It's mostly audible only at idle, but it does seem to increase in frequency with RPM. At ~3K it becomes faint and continuous, melting in with the engine noise. It sounds like it's coming from the passenger side, from around, or below the air pump.

What's weird is that it's really inconsistent. I may be completely fine after a whole day of abuse, and start doing it when I'm just out for a drive.

My guesses:

Carbon deposit? But then I would think the noise should occur all the time.

SSV? I believe that should be under the air pump, but from what I remember, the noise doesn't sound quite like that...

Something touching? That's kind of my working theory. Could a collapsed engine mount cause something like the exhaust manifold to touch the frame?

You can take a listen on the video, but unfortunately my phone slid of the engine cover when I started it, so it's a little muffled. It hasn't happened since, so I couldn't re-record.

Edited, cause I forgot to add the video.