Oracle APEX: ORA-40597 JSON path error with "Invoke API" process

I'm encountering an error:

ORA-40597: JSON path expression syntax error ('$.') JZN-00217: Key
step contains unexpected characters at position 2 error when using an
"Invoke API" page process in Oracle APEX (23.1+).

Goal: Fetch data from a Simple HTTP REST Data Source and populate page items on a form.

My JSON Response Body:

{   
  "Body" : {     
      "ResponseStatus" : { ... },     
      "isfMembInfo" : {       
                        "MemberFirstName" : "...",       
                        "MemberRank" : "...",       
                        "EmployeeNumber" : "..." 
                      } 
   } 
}

REST Data Source - Data Profile Setup: Row Selector: $.Body.isfMembInfo (This is confirmed in screenshots and matches the JSON structure.) Columns: Each column's Selector (Path) is correctly set to the direct key name (e.g., MemberFirstName, MemberRank).

APEX Page Process - "Invoke API" Setup: Type: Invoke API (On Load - Before Header) REST Data Source: (My configured RDS) Operation: fetchSingleRowUserISF (A GET operation requiring an EmployeeIdentifier input parameter, which is provided by a page item). Output Parameters: Mapped to page items using the Data Profile column names (e.g., MEMBERRANK maps to P1_MEMBER_RANK). The Problem:Despite the Data Profile being configured as described, the application errors out with ORA-40597

So when i add output parameter this error occurred.