Quoted verbatim from the breaking news section of http://www.immigration-law.com/
Updated 08/06/2002: IBIS Check Rule and Need for Prompt Passport Stamping of 485 Approval
AILA inquiry with the INS HQ indicates that once EB-485 is approved and people appear at the District Offices for passport stamping of temporary evidence of permanent residence and I-89 processing for plastic card production, the District Offices need IBIS check if 35 days have passed since the IBIS check undertaken by the Service Centers passed 35 days because the IBIS check is valid only for 35 days. When the stamping can not be granted because of such problem, the District Offices are instructed to give a temporary 30-day stamping so that people can continue to work and travel. It is thus strongly suggested that the people who receive the I-797 Approval Notices appear at the District Offices as quickly as possible to avoid such problem.
Updated 08/06/2002: IBIS Check Rule and Need for Prompt Passport Stamping of 485 Approval
AILA inquiry with the INS HQ indicates that once EB-485 is approved and people appear at the District Offices for passport stamping of temporary evidence of permanent residence and I-89 processing for plastic card production, the District Offices need IBIS check if 35 days have passed since the IBIS check undertaken by the Service Centers passed 35 days because the IBIS check is valid only for 35 days. When the stamping can not be granted because of such problem, the District Offices are instructed to give a temporary 30-day stamping so that people can continue to work and travel. It is thus strongly suggested that the people who receive the I-797 Approval Notices appear at the District Offices as quickly as possible to avoid such problem.