Can a domain be marked as "discovered" several times in NRD2 files?

No, a domain name cannot be marked as 'discovered' (meaning it was previously unknown and created more than 7 days ago) in NRD2 files more than once.

For example, consider Domain A, which was registered on January 1, 2022. NRD2 identified it about two months later and reported it as 'discovered' on March 11, 2022.

Now suppose Domain A was dropped after one year (in January 2023) and then re-registered on April 3, 2024. Even though we detected it again a month later (after more than 7 days had passed since the new registration) by NRD2, it will not be reported as 'discovered' a second time. Instead, it may be reported as 'updated' in the future.