Yeah, they are WRONG!!!! Box blisters, croc gets watermarks. There are some Epsom that will blister (I had one that did, I had one that didn't). Clemence can absolutely get wet!
That brought me to think, based on the above mentioned theory (see my previous post), between the 2 epsoms you have, what is the color of the one that blistered? Is it darker than the one that didn't blister?