How could it be more detailed? The person wrote that they haven't played the third game in a long time and haven't encountered any scrolls... So, they simply made a mistake; nothing disappears into thin air...

Exactly, thanks, Alan :) Not only do I not remember, but they're also deliberately confusing things. I can't explain it any clearer than in my first message: To avoid using the bug of selling at an inflated price, artifacts must be sold ONLY from the hero, not from the backpack.
PS. The last time I played the third game was twice here on this resource; now I'm playing the third game, and I don't remember ever finding a scroll. And here they're telling me what a powerful bug it is to sell scrolls at an inflated price, especially at the beginning of the game. This bug doesn't have a significant impact on official tournaments (unless a specific map is encountered). In my opinion, the most powerful bug is double casting – checking each battle for mana consumption is not easy, just like balancing income and expenses. But the double-cast bug can be used on any map and at the beginning of the game. It can be caught with careful checking. That's why saves at the beginning and end of each turn are needed, and this is stated in the rules, albeit poorly. What it means is that a save must be made every game day. Well, they'll send one save – the beginning of the first day, and another – the end of the second day. It can be checked, but the cost of checking will be higher. What's so difficult about writing in the rules – a minimum of two saves per day (beginning and end)? For super-difficult battles with numerous monster units, the player must have saves before and after the battle. This doesn't mean that they all need to be sent. The main thing is that, in case of a possible check, the player MUST provide them if the organizer needs them.