Which situation can lead to the issuance of an inadvertently issued registration number (IIRN)?

The situation that leads to the issuance of an inadvertently issued registration number (IIRN) occurs when a document is processed incorrectly or not processed at all. This irregularity in processing can result in a trademark application being assigned a registration number despite not having met all the necessary requirements for registration. In essence, if the USPTO's systems mismanage the paperwork or if there's an oversight during the examination process, a registration number might be generated even though the trademark should not have been registered at that point.

In contrast, successful registration after payment, successful trademark renewal, and correct publication without issues all reflect proper processes being followed, where the trademark meets the necessary legal requirements for those actions. Thus, these situations would not lead to an IIRN since they indicate that due diligence has been exercised by the USPTO.