What does 是是 mean beyond 是? Is it just a typo? 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。
  Baidu Baike，不约而同


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.
It is a typo here, but in some dialects 是是 means 是不是, which is another story.