PEGASUS extracting from input instead of abstrative summarization


When using PEGASUS_large with the summarization pipeline, all the model does is extract from the input. I am surprised by this as even if not fine tuned the pretraining should not have made the model learn to just copy full sentences. Any idea why this happens ?

The code I am using is the following:

model_name = 'google/pegasus-large'
model = PegasusForConditionalGeneration.from_pretrained(model_name)
tokenizer = PegasusTokenizer.from_pretrained(model_name)
summarizer = pipeline("summarization", model=model, tokenizer=tokenizer)
summary = summarizer(input, min_length=10, max_length=150,do_sample=True,no_repeat_ngram_size=3,num_beams=10)[0]['summary_text']

Using the API from the hugging face page prompt the same results (and thus also only extract).