I remember a similar problem I had with a ring-disc electrode. One was Pt, the other Au. When cleaning them by polishing, I achieved a similar "cross contamination", maybe by traces, as Chaitanya Kumar mentioned. I even suspected that I had produced a (surface) alloy, which I would also expect in your case. I think the only was polishing the electrodes separately, maybe one requires even different (alumina) powders, from rough to nano. I very much doubt that solvent rinsing helps. In the worst case, I would try cycling in chloride-containing sulfuric acid, to remove the top layer oxidatively.

If it is appropriate in your case, you can try electropolishing, both in the cathodic and anodic regions. Alternatively, you can use cycling with a large potential window. During cycling, you will be able to observe how the electrode is cleaned from impurities (as indicated by the oxidation peak of Au) with an increasing number of scan cycles.

In general, experience suggests that for accurate electrochemical measurements, it is better to avoid organics in the experiment. In your case, this is ethanol, impurities of which can firmly settle on the electrode.