A Design solution that was already proposed but skipped to reach short-term goals is considered a Design debt. Lack of budget, skilled devs, high dev-estimation, etc., are the usual reasons for such Design debt. It is essential to acknowledge the skip, mark it, and review it periodically.
Design debt should not be for documentation. Meeting standards is a basic quality expected in product building. Not following the standards will break standards while Implementing a design System practices and principles. This is especially critical while building consumer-facing products, as Software design should be opinionated.
To reduce Design Debt, it should be considered as a performance indicator. If it is solved, and when it is solved (Open UX Debt Age) should be considered an indicator of the product team’s performance evaluation.