It seems like the gong can be rung by one player, then is unusable for a period of time. My friend and I got there just as someone popped in from another realm and rang it. We had the experience you had. We couldn't interact with it in any way. A little later, my friend was able to ring it and activate the sigil but I couldn't. I decided to switch realms, and I found a gong that would ring. It worked and the sigil lit up. I agree that K I needs to tweek the respawn rate of the gong interaction box. I'm not sure why there is a wait for it at all.