why dose my finetuned model repeat the given prompt before generating its response

Million thanks to your great work! Could you help me with my problem? After I finetune my llama model, when I prompt it with text like "Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.\n ### Instruction: {my_instruct} ### Input: {my_input} ###Response:", the model does not only output the response part as I expect, it outputs the prompt above and then its response. my dataset looks like: my environment is: