diff --git a/scene/2d/tile_map_layer.cpp b/scene/2d/tile_map_layer.cpp
index 160733c2d93..4cf1380644a 100644
--- a/scene/2d/tile_map_layer.cpp
+++ b/scene/2d/tile_map_layer.cpp
@@ -838,6 +838,7 @@ void TileMapLayer::_physics_update(bool p_force_cleanup) {
 							physics_body_key.angular_velocity = angular_velocity;
 							physics_body_key.one_way_collision = tile_data->is_collision_polygon_one_way(tile_set_physics_layer, polygon_index);
 							physics_body_key.one_way_collision_margin = tile_data->get_collision_polygon_one_way_margin(tile_set_physics_layer, polygon_index);
+							physics_body_key.y_origin = map_to_local(cell_data.coords).y;
 
 							if (!physics_quadrant->bodies.has(physics_body_key)) {
 								RID body = ps->body_create();
diff --git a/scene/2d/tile_map_layer.h b/scene/2d/tile_map_layer.h
index 10194b79b27..4ea641df66e 100644
--- a/scene/2d/tile_map_layer.h
+++ b/scene/2d/tile_map_layer.h
@@ -243,14 +243,20 @@ public:
 		int physics_layer = 0;
 		Vector2 linear_velocity;
 		real_t angular_velocity = 0.0;
+
 		bool one_way_collision = false;
 		real_t one_way_collision_margin = 0.0;
 
+		int64_t y_origin = 0; // This is only used if one_way_collision is on, to avoid merging polygons vertically in that case.
+
 		bool operator<(const PhysicsBodyKey &p_other) const {
 			if (physics_layer == p_other.physics_layer) {
 				if (linear_velocity == p_other.linear_velocity) {
 					if (angular_velocity == p_other.angular_velocity) {
 						if (one_way_collision == p_other.one_way_collision) {
+							if (one_way_collision && y_origin != p_other.y_origin) {
+								return y_origin < p_other.y_origin;
+							}
 							return one_way_collision_margin < p_other.one_way_collision_margin;
 						}
 						return one_way_collision < p_other.one_way_collision;
@@ -270,7 +276,8 @@ public:
 					linear_velocity == p_other.linear_velocity &&
 					angular_velocity == p_other.angular_velocity &&
 					one_way_collision == p_other.one_way_collision &&
-					one_way_collision_margin == p_other.one_way_collision_margin;
+					one_way_collision_margin == p_other.one_way_collision_margin &&
+					(!one_way_collision || y_origin == p_other.y_origin);
 		}
 	};
 
@@ -280,6 +287,9 @@ public:
 			h = hash_murmur3_one_real(p_hash.linear_velocity.x);
 			h = hash_murmur3_one_real(p_hash.linear_velocity.y, h);
 			h = hash_murmur3_one_real(p_hash.angular_velocity, h);
+			if (p_hash.one_way_collision) {
+				h = hash_murmur3_one_32(p_hash.y_origin, h);
+			}
 			return h;
 		}
 	};