I just reread AFFC Cersei V and her recollection of sending Senelle to Qyburn really stood out to me for this detail:

The memory still made the queen queasy. The cells were bitter cold. Even the torches shivered. And that foul thing screaming in the darkness . . .

That “foul thing” is/was likely Gregor, who was relocated to the Black Cells specifically because he was screaming so much… but to scream, and still be screaming in Cersei V, requires a mouth.

But this is after Cersei apparently sends Balon Swann to Dorne with “Gregor’s head” in Cersei IV.

Is this definitive proof that the head in Dorne is a fake? (One of the dwarf heads, likely?) Or is there plausible doubt about the timeline (as in, Cersei sends Senelle to Qyburn prior to Cersei IV, but doesn’t recall it until Cersei V?) Or, could this have come post-head-transplant, if you believe in a new head on Clegane’s body?

Thoughts anyone?