Regarding the last part of the forecast

[ProgrammerSu]

Thank you very much for your code. I also ran the code myself. The result is similar to yours. Why does the last part of the predicted value look like this in the figure?

[ProgrammerSu]

Ok,I think I konw where the problem, thanks

[aixiaodewugege]

Hello，May you please state the cause of the problem？I meet the same qusetion,thanks