This question relates to the following snippet:
不约而同是一个成语，读音是是bù yuē ér tóng，意思是指事先没有约定而相互一致。
It introduces the chengyu (idiom) 不约而同, which means something like "doing something consistently, but without prior arrangement". I'm just wondering why 是是 is used here---I haven't seen this before, so maybe it just means 是? Or maybe it's a typo?
Question: What does 是是 mean beyond 是? Is it just a typo?
Putting 是是 into YouDao gives this example: 你认为将会是是错误的决策. Maybe it's more tentative than plain 是, like 看看 perhaps. I'm not clear on this.