So I found an article about Aset/Isis (You’re shocked, I’m sure!) and within it, the author spoke of Isis and Hera syncretism.
11-Festival of Hera Teleia
The article also says that this is a festival of Isis, but that she’s assimilated with Hera, so I’m not sure if this is an Isis festival, a Hera Teleia Festival or an Isis-Hera Teleia festival.
It also mentioned a triad of Zeus, Hera and Athena being honored. Hera also has an epithet called Hera of the Great Throne.
Bricault, Laurent. “Un trône pour deux.” Mythos. Numero 3, n. s., 2009, pp. 131-142. The festival itself is on page 136.