Maybe it will work for me too.

Yesterday, I decided to solve the problem differently: I downloaded Armageddon's Blade and quickly completed the first three scenarios from The Restoration of Erathia. And a miracle happened! All the checkboxes remained checked, and I can continue playing.

It's a pity that there isn't someone who has played through The Restoration of Erathia using the complete collection from Буки, so we could be absolutely sure that everything works.