I believe you are right about classes having something to do with drop rate of certain items.
You see, I played on the closed beta as an archer and when I got to the Ramstis Ridge I killed a couple of Desert Chupacabra and got the ears.The exactly same thing happened while playing this time also as an archer. (archer c2>ranger c2>rogue c2)
But this ideia just came to me when a friend of mine, who is a cleric, got her Fox Mask from the Madakias while we were grinding on Mausoleum 5F, cause guess whatā¦ the same thing happened on the closed, she got herself a mask but I never got one. (cleric c2>priest c3>krivis c1)
I got 3 more Desert Chupacabra Ears for some friends of mine, but couldnāt get one Fox Mask.
Those items arenāt rare and maybe it is just coincidence but it is weird to exist such a coincidence.