Bootstrap Navbar Jumps Repeatedly When Fixing On Top

I am working with a template and the navbar starts at the bottom of the first page, and has a strange movement when it fixes on top after scriolling. I am using bootstrap. Here you

Solution 1:

As Bruno above states, it is an issue with Bootstrap

"Yeah, I see it now. I found a lot of resources documenting this issue with bootstrap but i'm not sure how to solve it. Good luck. – Bruno 8 mins ago "