Hmmmmmm. Im having the same trouble. I have two totems but neither of them are producing the last piece of the gong, so I came here to see if there was an answer. I have racked my brain, do I not have the center of the mosaic or some other small thing wrong??

No piece of the gong appears. Have the other 3 pieces, tried two different totems which took forever to get. Neither works. Shouldnt I be able to see the 4th piece of the gong when it appears? I thought maybe I moved the totem too soon and should have waited for them to finish celebrating, cant think what I could be doing wrong.