RAMWorks posted at 5:11 PM Tue, 11 April 2023 - #4461814

Y-Phil posted at 3:59 PM Tue, 11 April 2023 - #4461792

Could it be the result of a problem with the bump bitmap?
I mean: I wonder if they appear with another one

No, the maps are fine, I would have caught that error if I was rendering with the Physical Node setup.  This seems to be Cycles but I just can't figure it out.  With no viewport feedback it's hard to fine tune and see things until I do a test render.  

Look at your Bump Node and adjust your strength value to 1.  I still believe that a node-set is off somewhere.