Short code not working when using dynamic values in forms

i have used the acf shortcode and its working fine when you enter the values manually.

Example below
[acf field="image_name" post_id="123"]

And when using a dynamic condition, it does grab the value but does not display the shortcode

Code below
[acf field="image_name" post_id="{dynamic.dropdown_1}"]

Here is my dropdown code

<select name="dropdown_1" data-name="dropdown_1" data-calc_value="0">
  <option value="">Select a Model</option>
  <option value="123">Vitara</option>
  <option value="6630">XL7</option>
</select>