diff --git a/blackboard/blackboard_plan.cpp b/blackboard/blackboard_plan.cpp
index 4545a6b..d55cd03 100644
--- a/blackboard/blackboard_plan.cpp
+++ b/blackboard/blackboard_plan.cpp
@@ -122,6 +122,7 @@ bool BlackboardPlan::_property_get_revert(const StringName &p_name, Variant &r_p
 
 void BlackboardPlan::set_base_plan(const Ref<BlackboardPlan> &p_base) {
 	if (p_base == this) {
+		WARN_PRINT_ED("BlackboardPlan: Using same resource for derived blackboard plan is not supported.");
 		base.unref();
 	} else {
 		base = p_base;
diff --git a/bt/bt_player.cpp b/bt/bt_player.cpp
index 54608b4..7840400 100644
--- a/bt/bt_player.cpp
+++ b/bt/bt_player.cpp
@@ -86,7 +86,12 @@ void BTPlayer::set_behavior_tree(const Ref<BehaviorTree> &p_tree) {
 }
 
 void BTPlayer::set_blackboard_plan(const Ref<BlackboardPlan> &p_plan) {
-	blackboard_plan = p_plan;
+	if (p_plan.is_valid() && !RESOURCE_IS_BUILT_IN(p_plan)) {
+		WARN_PRINT_ED("BTPlayer: Using external resource for derived blackboard plan is not supported. Converted to built-in resource.");
+		blackboard_plan = p_plan->duplicate();
+	} else {
+		blackboard_plan = p_plan;
+	}
 	_update_blackboard_plan();
 }
 
diff --git a/bt/bt_state.cpp b/bt/bt_state.cpp
index 749762f..ec1c64f 100644
--- a/bt/bt_state.cpp
+++ b/bt/bt_state.cpp
@@ -31,16 +31,22 @@ void BTState::set_behavior_tree(const Ref<BehaviorTree> &p_tree) {
 		if (p_tree.is_valid()) {
 			p_tree->connect(LW_NAME(changed), callable_mp(this, &BTState::_update_blackboard_plan));
 		}
+		behavior_tree = p_tree;
 		_update_blackboard_plan();
+	} else {
+		behavior_tree = p_tree;
 	}
-	behavior_tree = p_tree;
 }
 
 void BTState::_update_blackboard_plan() {
 	if (get_blackboard_plan().is_null()) {
-		set_blackboard_plan(Ref<BlackboardPlan>(memnew(BlackboardPlan)));
+		set_blackboard_plan(memnew(BlackboardPlan));
+	} else if (!RESOURCE_IS_BUILT_IN(get_blackboard_plan())) {
+		WARN_PRINT_ED("BTState: Using external resource for derived blackboard plan is not supported. Converted to built-in resource.");
+		set_blackboard_plan(get_blackboard_plan()->duplicate());
+	} else {
+		get_blackboard_plan()->set_base_plan(behavior_tree.is_valid() ? behavior_tree->get_blackboard_plan() : nullptr);
 	}
-	get_blackboard_plan()->set_base_plan(behavior_tree.is_valid() ? behavior_tree->get_blackboard_plan() : nullptr);
 }
 
 void BTState::_setup() {
diff --git a/hsm/limbo_state.h b/hsm/limbo_state.h
index 706045e..69bc2cf 100644
--- a/hsm/limbo_state.h
+++ b/hsm/limbo_state.h
@@ -67,7 +67,7 @@ protected:
 
 public:
 	void set_blackboard_plan(const Ref<BlackboardPlan> &p_plan);
-	Ref<BlackboardPlan> get_blackboard_plan() const { return blackboard_plan; }
+	_FORCE_INLINE_ Ref<BlackboardPlan> get_blackboard_plan() const { return blackboard_plan; }
 
 	Ref<Blackboard> get_blackboard() const { return blackboard; }
 
diff --git a/util/limbo_compat.h b/util/limbo_compat.h
index 690682b..321dc40 100644
--- a/util/limbo_compat.h
+++ b/util/limbo_compat.h
@@ -234,6 +234,7 @@ Variant VARIANT_DEFAULT(Variant::Type p_type);
 #define PROJECT_CONFIG_FILE() GET_PROJECT_SETTINGS_DIR().path_join("limbo_ai.cfg")
 #define IS_RESOURCE_FILE(m_path) (m_path.begins_with("res://") && m_path.find("::") == -1)
 #define RESOURCE_TYPE_HINT(m_type) vformat("%s/%s:%s", Variant::OBJECT, PROPERTY_HINT_RESOURCE_TYPE, m_type)
+#define RESOURCE_IS_BUILT_IN(m_res) (m_res->get_path().is_empty() || m_res->get_path().contains("::"))
 
 #ifdef TOOLS_ENABLED