6MT grind when slowing/stopping in gear

TorqueSteer

I had my manual transmission replaced by Nissan a few months ago. Just recently I started getting an odd sound, like a slight grind when stopping or slowing to a very low speed (5 mph or less) in gear, with the clutch all the way in. Sometimes it’s a long grind, and I can feel it in the shifter. But the sounds seems to be coming from deeper in the car, unlike a missed shift grind.

It happens intermittently and only when it wants to. So it’s difficult to replicate and for that reason I don’t want to take it back to the dealer unless I’m sure the can recreate it. Otherwise the transmission feels like butter. Clutch engagement and disengagement are fine.

Any thoughts on what this sound could be?