Sounds to me like that bike has been in an accident or has had some rough handling. Each item by itself may not cause an issue but the two combined might and what else may be tweaked that you don't know about? I'm just throwing out possibilities though, I'm no bicycle alignment expert, or even amateur. I know it doesn't take much of a misalignment to turn an automobile into an ill handling beast though.

By the way, welcome to the forum. Your English is fine, in fact it is better than some for whom it IS a native language.