Pick your banks I suspect is the answer, Bankia did not charge my Revolut cash but several others wanted to. So look around and when you get to the point where they say we will charge x for this transaction, press cancel and move on! Well that's what I did. However it may be that over time it will be an issue with all of them?
We've used a Caxton card for the last 5 years here in Spain, and all were free to use in the beginning. Now more and more Spanish banks are charging to use it . Two I know that don't are Caixa bank and Deutsche bank, but the trend is increasing.
We're currently looking at alternative ways to get money from our UK bank account, especially now that Brexit is looming over us.
It's nothing to do with Caxton, it's a general charge on any card not issued in Spain. So Revolut has the same problem. As mentioned Caixa don't seem to charge at present as well as some others. If you have Euros loaded make sure you ask for euros and not £££'s as you'll be charged conversion fees and a poorer rate.