Yep, sometimes error logs are cryptic and not really useful, not just a React thing.
The issue is that everything in your code was good, you were using GSAP Context and reverting it appropriately in the cleanup phase, so it had to do with something on the DOM.
React fragments can be useful in certain situations but I try to avoid using it as much as possible because of errors like this. When working on a SaaS project a few years ago I had my personal encounter with this error and it took my several hours to get to the problem. So my next try on your demo was to remove that and see how it works.
If possible move your links to a container that is placed in the layout file, it saves you from re-rendering them everytime. If the links should go on every page, then avoid using fragments. Clearly there is a problem when a node is being removed after the cleanup phase (most likely the next link component, which is causing this, but I can't tell you for sure.
Happy Tweening!