The strike specific loot for the restorative mind is now impossible to reach at the end of the strike because of the invisible walls which you all put into place. The problem is likely due to the fact that strikes are killing the boss much faster than "originally intended" and so the R. Mind isn't dying in the middle, but rather somewhere along his back and forth path along the outer circle. A good temporary solution for you bungie devs would be to make the middle part of the boss room where he finally ends his rotation if you don't kill him quickly to be open to all sides of the circle (eliminate the walls to the middle of the circle) and put the chest their floating on the magical blue stuff (even though that doesn't make sense) until you can figure out how to code the invisible walls because i bet that code is buried very deep. And for us players, the only real solution is to not kill the boss as fast, which is pretty hard to communicate across to random strike teammates.