How to reduce style injection time in browsersync?

Question

gulp.js

A couple of months ago, I noticed a significant increase in the time between styling and injecting them into the browser. At first, I sinned against the overgrown template, but after the maximum simplification of the template, there was no doubt left, the culprit was browsersync itself. Compilation of scss, autoprefixer, csscomb and minification work out in a matter of milliseconds, while refreshing the page in the browser can take 3-5 seconds. Remarkably, the border is very sharp. When changing the style file to ~500 lines, the page reloads almost instantly. > 600 lines, and the delay already clearly interferes with comfortable work.
Mb, someone faced and can explain the essence of such strange behavior?
Win 10
Node v6.9.4
gulp v3.9.1
browser-sync v2.18.6

browserSync.init({
        server: {
            baseDir: "app"
        }