Is the Orb of Etheria still locked to the lowest difficulty you've ever played? If so, is there any fix for this?

According to this guide, the Warlords Battlecry II campaign has an issue (probably a bug?) that causes the Orb of Etheria (the reward you get for beating the campaign) to drop based on the lowest difficulty of campaign mission you’ve ever played, even if you reset the entire campaign and play through the whole thing at higher difficulty. In other words, if you ever play a campaign mission at any difficulty below the highest, that’s it, you’re locked out of ever receiving the best rewards.

Thirdly, the difficulty for your hero is tagged to the lowest you’ve played (A bug?). This means that if you initially complete the Campaign in Extreme difficulty, and for the second time, 66 territories in Extreme and one in Easy, you will get a Godly Orb of Etheria for your first try, the Silver Orb of Etheria for your second, and for the third time, if you play all 67 territories in Extreme difficulty, you will still get the Silver Orb of Etheria. The difficulty is locked to the lowest difficulty you’ve played, so even if you still complete the Campaign for the fourth and fifth time in Extreme difficulty, you will still get the Silver Orb of Etheria. Better start with Extreme difficulty, and stick with it.

The guide is written for version 1.03 of the game. The playable version from GOG is 1.04, so it’s possible this bug has been fixed, but I’m unable to find patch notes or a changelog for the 1.04 version, so I’m not sure.

If it’s not fixed in the 1.04 patch, is there any way for me to manually correct the issue? I’m willing to cheat (e.g., edit save files) if necessary, but from what I can see the saves aren’t stored in a human-readable format.