Based on the provided legal document, the key legal principles and findings are as follows:

1. Jurisdiction of the Authority: The Competent Authority does not have the jurisdiction to issue a corrigendum that results in a substantial and material change to a previous order unless such authority is expressly conferred by law. Corrections are limited to clerical or typographical errors and cannot alter substantive rights or the original order's core content (!) (!) (!) .

2. Nature of Corrigendum: A corrigendum is meant to correct obvious clerical or arithmetical errors, not to effectuate a review or substantive change in the original order. Issuing a corrigendum that materially alters the original decision exceeds the inherent powers of the authority and is impermissible (!) (!) (!) .

3. Principles of Natural Justice: The issuance of a corrigendum must adhere to principles of natural justice, including providing notice to affected parties and recording reasons for the correction. Failure to do so renders the corrigendum arbitrary, unfair, and violative of constitutional rights (!) (!) (!) .

4. Recording of Reasons: Orders that prejudicially affect rights must be supported by clear, cogent, and succinct reasons. Lack of reasons in the corrigendum leads to a miscarriage of justice and renders the order unsustainable (!) (!) .

5. Material and Substantive Changes: When a corrigendum results in a significant change in the land conveyed—such as increasing the area substantially beyond the scope of a correction—it is considered beyond the permissible correction of an obvious error. Such actions are unlawful unless challenged through proper legal proceedings, not via a corrigendum (!) (!) .

6. Functionality of the Authority: Once an order of conveyance is passed, the authority generally becomes functus officio and cannot review or alter its order unless explicitly authorized by law. Any attempt to do so without legal basis is invalid (!) (!) .

7. Legal Recourse: If a corrigendum is improperly issued, affected parties retain the right to challenge the original order or the subsequent conveyance through appropriate legal channels. They should not rely solely on a corrigendum to rectify substantive errors (!) (!) .

8. Overall Conclusion: Corrigenda that go beyond correcting clerical or obvious errors and instead effect substantial changes in rights or land conveyance are unlawful. Proper legal procedures must be followed for such corrections, including providing notice and reasons, and respecting the authority's jurisdiction limits (!) .

In summary, the authority's power to issue corrigenda is limited to minor, clerical corrections. Any correction that significantly alters rights, land area, or substantive terms without following proper procedures is invalid, and affected parties have the right to challenge such orders through appropriate legal avenues.