diff --git a/Core/Models/Eft/Common/Tables/HandbookBase.cs b/Core/Models/Eft/Common/Tables/HandbookBase.cs
index ef2d0372..58eb73b4 100644
--- a/Core/Models/Eft/Common/Tables/HandbookBase.cs
+++ b/Core/Models/Eft/Common/Tables/HandbookBase.cs
@@ -17,6 +17,7 @@ public class HandbookCategory
     public string? Id { get; set; }
 
     [JsonPropertyName("ParentId")]
+    [JsonIgnore(Condition = JsonIgnoreCondition.Never)]
     public string? ParentId { get; set; }
 
     [JsonPropertyName("Icon")]