Will fine tuned model only works on same pattern data which it is fine tuned on

I am new to fine tuning ,my question is : I have fine tuned ada base model , for finding bugs in python code ,Now if i send a prompt ,“HI” ,I expect that to respond by greeting me back again as “Hello” ,But it responded me in a weird way which is far away of greeting me back ,Below is the response of the model

Response :“Mobile Networks Considerations
CHAPTER 9 Hints To Use When Purchasing Wireless Mニュースの電話(wired)電話 の選択 Iglu キャンペーン の電話 の選択 電話シャッフ”

So fine tuned models doesn’t have knowledge on the basic prompts ?
It only works with the prompts with the similar format/pattern ?