Hi - great work on RU BTW.
Hw-env: RaspberryPi 2
I am having a problem with Global Random on my RPI3 (not 2 as listed above). It definitely adds a new song to the queue in the expected manner. Unfortunately it seems to draw the same songs in the same order every time. I don't know how it's implemented but it might be that the seed for the random number generator is fixed (rather than extracted from say the system clock or thermal noise or something like that). The only workaround (which I'm not 100% sure of yet) is to leave the system powered up all the time, which may stop the random number generator going back to the start of its list.
My default method of listening is almost exclusively letting the machine decide which music to play, so I really notice it. I can imagine it becoming a problem for anyone who tries global random however. So far I've only found one other reference to it on this forum.