The windshield wipers on one side chatter?

Hello,

This could be due to bad wiper blade or the spring on the wiper arm is too weak to have enough pressure on the wiper blade to make smooth contact as it sweeps back and forth.

Make sure there is no dirty or debris stuck under the wiper blade as that can add more friction and create this type of issue as well.

https://www.2carpros.com/articles/how-to-replace-windshield-wiper-blades

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.