Animation not interpolating exported variable

Godot Version

4.5.1

Question

I am trying to animate an export variable using animation player a vector2 to be specific:

@export var position_offset : Vector2 = Vector2.ZERO : set = set_offset_position
....
func set_offset_position(new_offset: Vector2) -> void:
	#
	position_offset = new_offset	
	print(position_offset)

In the animation player i can add a track for the variable, i set the update mode of the track is continuos but when i run the animation the update is like the discrete case, so position_offset is updated only during the keyframes, not in between, the print output is something like this:

(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 0.0)
(0.0, 10.0)
(0.0, 10.0)
(0.0, 10.0)

am i doing something wrong, or simply missing something?
thanks for your help

Make sure that your animation track update mode is set to “continuous” and interpolation mode to “linear” or “cubic”.

yes track update is set to “continuous” an interpolation mode to linear. Also i have forgot the routine is a tool, so it runs in the editor

What happens when you run the scene?

Look, i feel stupid but i found the problem: i tried to do the same thing in a dummy empty project and everything worked. Then i noticed than in my project i had this strange error when i added a keyframe:

I could still set the values but initially i always had this error.
What i did is:
1 delete all tracks with this variable, including the reset one
2 restart the project.
Now if i add again the track everything works as expected. So i do not know if something was corrupt or some kind of a bug or something else but now it works
Thanks @normalized for your help