Glitchy hamburger after interection

Hi, can somebody please help? I’ve been trying to sort this out for a few days. My hamburger is meant to change colour as you scroll the page and works perfectly until you open and close the nav menu. It then seems to stop working as before and becomes glitchy.

Can you spot what’s wrong?

Thanks,

Jono

https://project-tribal.webflow.io/draft

https://preview.webflow.com/preview/project-tribal?utm_medium=preview_link&utm_source=designer&utm_content=project-tribal&preview=d3103cf73eef3cfb91778788757fedb3&pageId=63ceed85a8626ac8dbc1ffcf&workflow=preview