The delay happens when displaying data in a repeater because when the repeater item is ready, I have only an English value that is stored in the collection ( value of the drop-down option). And after that, I have to load a Russian text for that value from another collection ( label of the drop-down option) with a separate request. And it works as expected. Maybe I just need to get rid of that extra-request somehow.
And there is another problem with updating data in a form described here