### Godot version

v4.1.rc2.official [46424488e]

### System information

Godot v4.1.rc2 - Windows 10.0.22621 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 3060 (NVIDIA; 31.0.15.3623) - AMD Ryzen 7 5700G with Radeon Graphics (16 Threads)

### Issue description

When setting the AnimationTree to active, Godot crashes.

### Steps to reproduce

https://github.com/godotengine/godot/assets/46705245/dbe5eb81-1357-43e8-ac80-a4eb97eea9fc

### Minimal reproduction project

[Crash.zip](https://github.com/godotengine/godot/files/11945826/Crash.zip)

StringName node = start_request;
			ERR_FAIL_V_MSG(0, "No such node: '" + node + "'");
		}
	}
	if (travel_request != StringName()) {
		
		String travel_target = _validate_path(p_state_machine, travel_request);
		Vector<String> travel_path = travel_target.split("/");
		travel_request = travel_path[0];
		StringName temp_travel_request = travel_request; 
		
		Vector<StringName> new_path;
		bool can_travel = _make_travel_path(tree, p_state_machine, travel_path.size() <= 1 ? p_state_machine->is_allow_transition_to_self() : false, new_path, p_test_only);
		if (travel_path.size()) {
			if (can_travel) {
				can_travel = _travel_children(tree, p_state_machine, travel_target, p_state_machine->is_allow_transition_to_self(), travel_path[0] == current, p_test_only);
			} else {
				_start_children(tree, p_state_machine, travel_target, p_test_only);
			}
		}
		
		if (can_travel) {
			path = new_path;
		} else {
			
			if (p_state_machine->states.has(temp_travel_request)) {
				path.clear();
				if (current != temp_travel_request || reset_request_on_teleport) {
					_set_current(p_state_machine, temp_travel_request);
					reset_request = reset_request_on_teleport;