If your potentiometers are not connected to the Axoloti itself, adding a capactor is probably the way to go.
What you can try is to add the MIDI CC to a ctrl/dial p object, run that one through a math/smooth object and then to the inlet of the parameter you want to control. Normally you would add the MIDI CC to the dial on the object itself.
Thank you, I’ll try with the capacitors 
What about the midi I already have something similar to your suggestion in my patch but the attenuverter case is different, like the following sketch
I need to smooth (or apply krate lpf) the behavior of the control of attenuverter. 
Hi, I tried to place the ceramic capacitors as you suggested but the pots became more unstable with than without it 
I also tried with 10pF and 432nF but the result is the same 
