Why does the IFrame reload OK if it loads a child IFrame with a Unity WebGL game?

Question

JavaScript

I download the application, log in to it through OKAPI. I start the game and the first time I start it, the main game IFrame is reloaded.
I tried to catch the error but there are no errors. I watched at what point the frame was reloaded, it turns out that it does not even have time to execute the logic of the child frame with the game and restarts.
However, after the next launch (after the frame is reloaded by an error), the game loads as it should.
This problem is located both in Odnoklassniki and in My World.