Though I don't use Alclad, it' s possible that if you applied a gloss black primer coat as the instructions recommend for the high sheen finishes, perhaps you didn't apply a full coat of the polished aluminum.
Against a contrasting black background, even a light coat shows up very strongly, even if in reality it is little more than a mist coat. Then, when you apply a clear coat on top, particularly if the clear coat is also lacquer based, it disperses the metallic coat somewhat, rendering it translucent, causing "show-through".