Well, i've been testing it and it still occurs. Also, it seems the sword actually disappears, as in the final boss of my game (Adventure of Ink) the player can collect a golden sword before the fight, but if they gain some xp before the boss, the sword dissapears and the player does only 1 damage.
Now the engine displays item details in this description modal.
For the swords, I added:
"Collectible steel sword: when equipped, increases the player's attack damage (the strongest weapon). Breaks after a few hits."
But you gave an excellent suggestion about making weapon durability optional. That could be implemented as a simple checkbox.