XT derailleur troubleshooting

The set up is: 10 speed DA bar ends, 9 speed XT derailleur medium cage, 11-32 SLX cassette 10 speed, 4601 10 speed chain, 50/34 FSA 10 speed chainrings, with the 34/32 ratio set up as below:

Problem is I’m getting some grinding somewhere when in the 50t chainring riding in the mid-low end of the cassette. Chain length when it starts to sound grindy in the 20t sprocket with a pretty straight chainline:

What I’ve done to troubleshoot:
Adjusted the B screw to where it is currently in the top photo
Removed the KMC chain I had on before for the current
Changed chainrings from FSA to sram
Extended cable housing length

Shifting is tuned and it’s not an issue with trimming the front derailleur. I mostly ride country roads where the surfaces are mostly smooth, albeit the bitumen has a rather ‘dead’ feeling. The only other thing I can think of is the tab in the cage, and that the chain is rubbing due to bumps in the roads (tab shown below). The chain clears the tab a good 2mm normally.

Can anybody shed some light? Overcome a similar issue?

4601 is a tiagra chain right?
Technically shimano has seperate chains for road and MTB in 10 speed, they have different shift plates. It may help a touch to use a xt/slx chain but I’d doubt that is caused of all the noise.

(They have gone back to the same chain for road/MTB in 11 from what I recall)