GPT-2 last sentence-trunication

I have a question about text generation and GPT-2. when I generate text with GPT-2 model sometimes the last sentence is not a proper sentence for example :

Once upon a time, there was a group of new immigrants and their son who at the beginning of World War II once began a long run of the most inhumane abuse they had been involved in. At the age the so-snappy, one

I wonder is there a way to handle this issue.I’ve checked Preprocessing data and used different values for padding and truncation but the problem still remains the same.
also, I tried to use <|endoftext|> in the tokenizer but it didn’t work.

thanks :slightly_smiling_face: