I actually have the same "issue". some people have more aggressive sweat composition than others.
I learnt it the hard way (stripped paint from an AL frame, than my look 381 lugs - AL - got the color all "bubbled", when i was running shimano DA7700 the levers and crank would get strange discolorations... and cable replacement was a monthly issue in summer).
The thing is - i live in Israel. so hot and humid... IIRC you are in northern Europe, right? so you do not get to "explore" your sweat as much as where it's hot and humid
your Mallorca experience has been just that - hot and humid.
Anyhow - this taught me to choose full carbon (incl lugs) frames; carbon crank set & levers etc, which is overall a good idea (going to campy, that is).
don't be alarmed... its natural (for some, anyhow).