You can safely ignore this error.
One of the specification authors wrote in a comment to your question but it is not an answer and it is not clear in the comment that the answer is really the most important one in this thread, and the one that made me comfortable to ignore it in our Sentry logs.
This error means that ResizeObserver was not able to deliver all observations within a single animation frame. It is benign (your site will not break). – Aleksandar Totic Apr 15 at 3:14
There are also some related issues to this in the specification repository.