ToME: the Tales of Maj'Eyal

Short description.
Heart of the Sandworm Queen remains in character's inventory after corruption.
Actual result.
The corrupted heart appears in character's inventory along with its normal version.
Expected result.
Only corrupted heart in character's inventory after corruption.
Steps to reproduce.
N/A.
Game version.
1.5.9 for windows from ToME site.
Comment.
There was only one heart obtained after defeating the Queen. After auto-explore the character was somewhere around position "1". Grand Corruptor was in "2". Actions were something like: Noggin Knocker -> Kill Shot -> Grand Corruptor moves to "3" -> Kneecapper (pinned) -> Swift Shot and normal shots until he fell in "3" (I don't think he used any spell before dying). After resting the character moves to "3" to pick up the loot. A message appeared about Scorpion's Tail and a dialog about corruption (accepted corruption). In character's inventory there were two hearts: 1 corrupted, 1 normal. Then auto-explore moved the character to "2" and another dialog about corruption appeared (accepted corruption).
Before I get there again I can only speculate about what happened. Maybe because the red circle tile "3" was occupied by an item (Scorpion's Tail) or lore window that appeared after picking that item up prevented the game from removing the normal heart correctly.