Staff have not said in Sneak Peek that it will ever refresh:
They just said it is added to the game in October and that’s all.
Just this page tells it will reset:
- What is the Fated Summon? — Empires & Puzzles Help Center
The refresh interval is not mentioned here.
Some people received answers from support about it will reset twice a year (so about 180 days apart), which is match with our Oracle’s latest prediction.