We have duplicate leads coming in from the web forms. We found a lead in the system where 8 duplicate records were created in Marketo from the same form, and same details. The time-stamp on all the records is almost the same. When I tested at my end, the form worked fine and no duplicates were created. Any idea how this might have happened?
If the form is reposted very rapidly in a short timeframe (as you say, the timestamp is almost the same) this can happen because the inserts do not see the existing records yet, so do not perform a merge.