“Heroes of Might and Magic V: Tribes of the East”

So, is there absolutely no way to fix this? Not even in theory?

If we're talking about a licensed version of the game, you can simply open almost any free-play scenario and find both upgrades there.

If we're talking about modifying campaigns, that's a completely different question.
There's no need to modify the campaign. :)

You still haven't specified exactly on which maps this happens, whether it's in the campaigns, whether it's a licensed game, whether it happens on all maps, etc. Because of this, it's impossible to help you.