Autocomplete rule to default Succession Plan Name from Incumbent field is not working

Summary:

Autocomplete rule to default Succession Plan Name from Incumbent field is not working. the plan name defaults for the first time when the incumbent has been selected. but if the incumbent is changed, the plan name still holds the previous value.

Content (required):

PPR has been also configured properly on the Plan Name field using Page Composer.

Version (include the version you are using, if applicable):

23B

Code Snippet (add any code snippets that support your topic, if applicable):