Gear box

[Genty94]

Currently driving the Tucson 2016 reg 1.7 diesel.

Got in the car to drive to work, changing through gears, got to 4th and noticed it crunched slightly. It’s been on going, gear change is still smooth and there’s no resistance in the change. It just makes a slight crunch noise. It’s now started doing it in 6th gear…

Has anyone had a repair done on the gear box or a similar issue? Any ideas what it could be?
Best route to go down?

Thank you!