Musical Gate Tuners have disappeared

After retrieving 2 tuners and putting them into the gate during the “Final Souldown” mission, I retrieved the third tuner (the one on the bottom right of the map). However, after falling a few times while carrying the tuner to the top right doing the parkour, the tuner respawned where it originally was. However, I could not carry it. It gave the prompt to click it to carry it, but it was unresponsive. I returned to main menu and loaded back in, however, now all 3 tuners had despawned and there were no tuners in the gate at all. (see attached: there is an image of the gate with no tunres, and an image showing the spawn point of the third tuner, which is now empty. All the other tuners are gone from thier original spawn points as well).