请问 a genuine mistake 什么意思？

原句如下：This was a genuine mistake, but it did cause me some worry... 我想如果是 mistake ，那 cause me some worry 很正常，为什么要用 but 作转折呢？所以我觉得 a genuine mistake 可能有别的意思，而不是“一个真实/诚恳的错误”。请各位高人帮忙解答，谢谢！

___ it be a mistake? I made a temble mistake it was quite a serious mistake,____caused Was the Appeasement a Mistake ( WW 2) 请问下Genuine Intel 是什么意思 It was a mistake not to buy a better car "that must be a mistake" "no,it______a mistake" 请教:翻译"a case of mistake" to make a mistake is human.翻译下下！！ Likes a person havin the mistake!这句话什么意思.