The built-in Instagram browser does not open the site (SPA) in the same way. What to do?

Question

Instagram

The built-in browser Instagram (Facebook, ..) opens the site incorrectly, that is, the DOM is loaded but there is no data, the mount() method of the Vue component is not executed.
Google Chrome and other browsers open normally.
Vue2, bootstrap3, flexbox were used.
Maybe there are limitations or how to optimize for them.

Answer 1

It's decided. There was a script on the page using ES6 features)), which do not work on older browsers and, accordingly, in the Instagram In-App browser