I’m not able to reproduce this problem. Since the element with id user_synonyms is already part of the initial html, it cannot be a timing issue. So my next best guess was, that my e.detail.newBody + MutationObserver hack is failing once more. But this hack only applies to turbo page navigations, not to page refreshes, so I guess this can be ruled out as well.
Maybe there is a conflict between scripts? What other scripts are you using?