On COMPASS, Controls must be set to "Implemented" to unlock related tasks. Without this, you cannot edit, upload artefacts, or perform any task activity, and it will negatively affect the compliance percentage. Tasks linked to those controls remain locked, and the overall compliance percentage will be adversely affected.
For more details refer Setting Control Status & Frequency
Start Date and Implementation Date for controls
These dates are required for the compliance percentage to be calculated accurately for the relevant time period.
Refer to How is compliance calculated on COMPASS?