I have the following code in my gulp file:

...
function styles () {  
  browserSync.init({
    proxy: "https://localhost",  //use your own server uri
    port: 8000  //use your own port
  });

  return gulp.src(paths.scss.src)
  .pipe(sourcemaps.init())
  .pipe(sass().on('error', sass.logError))
  .pipe(gulp.dest(paths.scss.dest))
  .pipe(browserSync.stream()) 
}

const build = gulp.series(styles);
gulp.watch(paths.scss.watch, build);  

exports.default = build

As you can see browserSync.init is being called every time styles event runs. styles runs on every change in scss files. The first time browserSync.init ran, it opened a new tab in the browser, but I expect it to do that every time styles run -- which doesn't happen, why?