Using BrowserSync in backend can make sense (e.g. when using the Classic Editor or dedicated Gutenberg editor styles from the theme).
However, POSTing updates to posts/pages can be quite problematic because this can overwrite the contents of other posts/pages, open in other tabs at the same time.
Also BrowserSync tries to reload the Gutenberg editor pages each time some styles were changed.
Would it therefore make sense to add a BrowserSync exception/filter/ignore to sage9 repository?