They are bugged, have been all season since they were re-added, no acknowledgement or response from Bungo so they don't care.
I have a friend who says they found a way to get them to proc by doing them back to back on both of the elements that are the active surge.
I tested now with void surge active and did the melee, grenade, super medal, and still nothing popped.
Also this clip I mentioned earlier was made today before reset and I was on void (I think the surges change weekly): https://youtu.be/5AUr8HE5mXY .
Unless your friend says he did on both active surges, void and stasis for instances are the active surges today. But there are no way you can do that in quick succession as the super doesn't recharge that fast.
Yeah you need to do it twice once on each element that are the surges back to back or so my friend claims, can't confirm it works personally. So even if that works its pretty difficult to setup as you would need orbs on the floor to get the super back etc.