Speaking of the TBM (Sound/Engine Issue)

For a while people were talking about the engine sounds changing, as if you are in a tube or tunnel. I've had this a few times lately and for the second time noticed the torque changes with this sound. I can be sitting at 115 on the torque, one notch below red line, 850 mode on and IS open. The sound will change and torque will drop immediately to around 100, and I think it even surpassed red line for this reason once. If I readjust the power lever the issue resolves. I have no spikes in my hardware and this is the only plane that this anomaly happens in. No other Black Square or any payware has sound or engine fluctuations. What is going on here?

I posted that to the JF forums, but I wanted to see if anyone is still experiencing this?  I have failures off on this plane.  Overall the flights are uneventful, but this is one issue that seems like a bug.  I mean I'm not touching any controls, condition lever is full forward, prop set to 1900, power a notch or so below red line, inertial separator off, 850 mode on, bleeds auto, no icing conditions.

Obligatory screen cap, on final to PSP 🙂