Posts from Spells disappear from the spellbook. Auto-translated

Hello, when playing a map with a large number of towns for an extended period, the best spells gradually disappear from the spellbook, being replaced by spells of levels 1-3 because there is no more space. Has anyone encountered this, and if so, how can it be fixed?

To help us understand the issue, please attach the save files from BEFORE and AFTER the spells disappeared to your message. Specify which hero the spells are disappearing from and which spells are affected. Also, please specify the exact version of "Heroes" you are playing, and if it's a mod, which version of the mod. If the game was downloaded from the internet, please provide a link to the source.
The most likely cause is an issue with your version of "Heroes".
It might also be worth asking: did you turn the pages in the spellbook? There was a recent case where a "disappearing" spell was actually just located where it should be. Or maybe you accidentally switched between the magic school tabs – that could also cause the spells to "disappear"?
I've attached a screenshot for your reference.

downloaded from Rutracker https://rutracker.org/forum//topic/5139371/
hero Mutara Drake
also, this happens during long campaigns, in general, when playing for a long time
uploaded the archive:
2 screenshots, before and after
2 save files
and the map I'm playing on

I apologize for the long post; I was working on it when I saw the corner brackets at the top. Thank you very much.

The map, by the way, seems interesting (The Dragons Heart). I haven't played it yet. When you finish it, maybe you can tell us about it and share your impressions?

I liked the map; it's long, interesting, and has many side quests from the fortune tellers' huts. I highly recommend it.

Thank you, I've noted the map and added it to my future plans. Please, tell us a little bit about the maps that are interesting to you, especially the lesser-known ones.