Need advice with render settings...images attached

ok thanks

it can be 2 different things :

Please have a try with IM+LC + DE to see if it's IM related.

You DMC settings are strong, you can check/modify those on the SR preset.

What are the actual SR dmc AA min, max and thr values ?

only if the reflect and/or refract buttons near "interp.glossies in Irrad map.." caption in SR configuration.
Technically it checks for you the "use interpolatation" in material reflect/refract options.

Hmm looks like it's AA related.
perhaps you can modify the preset (via the edit button) and change settings like this (for example) :
- replace the production AA noise thr from 0.005 to 0.003
- replace the prod min subdivs from 2 to 3

save preset with a new name

I would suggest to have a try in universal mode and/or bigger resolution, then downsample in photoshop