The recruiting lead has a list of open roles, while HR has a worker roster. The lists don't have the same grain: one row represents a position in the first list and a person in the second. Before explaining a difference in totals, inspect both populations and keep the identifiers visible.
A filled position with no matching worker should be investigated. It isn't safe to convert every such record into a recruiting vacancy automatically. An open position is a stated staffing status, while a missing relationship can be a data-quality defect. This case ends with a decision about what the recruiting lead can use now and what needs a separate reconciliation.