### 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)

}
	
	if (fading_from != StringName()) {
		double fade_blend_inv = 1.0 - fade_blend;
		fade_blend_inv = Math::is_zero_approx(fade_blend_inv) ? CMP_EPSILON : fade_blend_inv;
		if (is_start_of_group) {
			fade_blend_inv = 0.0;
		} else if (is_end_of_group) {
			fade_blend_inv = 1.0;
		}
		float fading_from_rem = 0.0;
		if (_reset_request_for_fading_from) {
			_reset_request_for_fading_from = false;
			fading_from_rem = p_state_machine->blend_node(fading_from, p_state_machine->states[fading_from].node, 0, true, p_is_external_seeking, fade_blend_inv, AnimationNode::FILTER_IGNORE, true); 
		} else {
			fading_from_rem = p_state_machine->blend_node(fading_from, p_state_machine->states[fading_from].node, p_time, p_seek, p_is_external_seeking, fade_blend_inv, AnimationNode::FILTER_IGNORE, true); 
		}
		
		if (fading_from_rem > len_fade_from) { 
			len_fade_from = fading_from_rem;
		}
		pos_fade_from = len_fade_from - fading_from_rem;
		if (fading_pos >= fading_time) {
			fading_from = StringName(); 
		}
	}
	
	if (rem > len_current) { 
		len_current = rem;
	}