https://yandex.ru/support/webmaster/robot-workings/ajax-indexing.xml?lang=en
You should not place the meta tag in the HTML version of the document. If you do so, the page will not be indexed.
use:
var prerender = require('prerender');
var rem = require('remove-meta-fragment-prerender')
var server = prerender({})
server.use(rem.removeMetaFragment());
server.start();