Are some randoms more random than others?

[tinkthank]

I know that some units get random magic picks ranging across the whole board, while others only get random elemental or random sorc picks. My question however is this:
For those units which get a random pick from all 8 paths, is it the case that one (or more) paths come up more often than others (weighted randomness)? I am thinking here for example of Machaka Black Sorc, where I get a random death more often than a random anything else, and almost never a random astral, or S&A Celestial Master, where of the 2 I get a random water very frequently -- is this just my odd luck or are the random picks weighted in some cases?