fix

src/entities/cargo/log.rs

@@ -57,7 +57,7 @@ pub fn spawn_log_cargo(
     );
 
     // Find nearest free tile from biased position
-    let drop_pos = tilemap.find_nearest_free_cargo_tile(biased_pos, 4)?;
+    let drop_pos = tilemap.find_nearest_free_cargo_tile(biased_pos, 4, &[])?;
 
     // TODO: OuchEvent — if a living entity occupies drop_pos, they take impact damage.
     // Check tilemap occupancy here when the combat/injury system exists.

src/entities/tasks/demo.rs

@@ -283,13 +283,21 @@ pub fn demo_system(
                 let idle_dorfs: SmallVec<[Entity; 8]> =
                     idle_dorfs.into_iter().map(|(e, _)| e).collect();
 
+                // Track destinations reserved this tick to avoid assigning the same tile
+                // to multiple dorfs before any have physically dropped their cargo.
+                let mut reserved: SmallVec<[IVec3; 8]> = SmallVec::new();
+
                 for dorf_entity in idle_dorfs {
-                    // Compute haul destination fresh for each assignment —
-                    // as logs accumulate near origin, each new assignment correctly
-                    // finds the next free tile.
+                    // Compute haul destination fresh for each assignment,
+                    // excluding tiles already reserved this tick.
                     let dest = tilemap
-                        .find_nearest_free_cargo_tile(IVec3::ZERO, HAUL_DEST_SEARCH_RADIUS)
+                        .find_nearest_free_cargo_tile(
+                            IVec3::ZERO,
+                            HAUL_DEST_SEARCH_RADIUS,
+                            &reserved,
+                        )
                         .unwrap_or(IVec3::ZERO);
+                    reserved.push(dest);
 
                     let Some((log_entity, log_pos)) = unassigned.pop_front() else {
                         break;

src/entities/tasks/executor.rs

@@ -276,7 +276,7 @@ pub fn task_executor_system(
                                 if chosen_drop.is_none() {
                                     *chosen_drop = Some(
                                         tilemap_mut
-                                            .find_nearest_free_cargo_tile(*dest, 8)
+                                            .find_nearest_free_cargo_tile(*dest, 8, &[])
                                             .unwrap_or(*dest),
                                     );
                                 }
@@ -331,7 +331,7 @@ pub fn task_executor_system(
                                 if chosen_drop.is_none() {
                                     *chosen_drop = Some(
                                         tilemap_mut
-                                            .find_nearest_free_cargo_tile(*pos, 8)
+                                            .find_nearest_free_cargo_tile(*pos, 8, &[])
                                             .unwrap_or(*pos),
                                     );
                                 }

src/world/tiles/tilemap.rs

@@ -467,8 +467,18 @@ impl TileMap {
     /// Uses a spiral outward search — O(radius²) worst case but returns immediately
     /// on first free tile found. Searches only at origin.z (same z-level).
     /// Returns None if no free tile found within radius.
-    pub fn find_nearest_free_cargo_tile(&self, origin: IVec3, max_radius: i32) -> Option<IVec3> {
-        if !self.cargo_tiles.contains_key(&origin) && self.is_standable(origin) {
+    /// Excludes any tiles in `exclude` from consideration — useful when
+    /// reserving multiple destinations in the same tick.
+    pub fn find_nearest_free_cargo_tile(
+        &self,
+        origin: IVec3,
+        max_radius: i32,
+        exclude: &[IVec3],
+    ) -> Option<IVec3> {
+        if !self.cargo_tiles.contains_key(&origin)
+            && !exclude.contains(&origin)
+            && self.is_standable(origin)
+        {
             return Some(origin);
         }
 
@@ -483,7 +493,10 @@ impl TileMap {
                         origin.y + dy * ITILE_SIZE,
                         origin.z,
                     );
-                    if !self.cargo_tiles.contains_key(&candidate) && self.is_standable(candidate) {
+                    if !self.cargo_tiles.contains_key(&candidate)
+                        && !exclude.contains(&candidate)
+                        && self.is_standable(candidate)
+                    {
                         return Some(candidate);
                     }
                 }