I hope this helps.
Yes, there can be a lag time from the date the transaction occurs to the first date of public availability. Each county has different response times in making sold data available in the public records for that jurisdiction. Our data sources provide regular updates to the assessor and deed (sold) data on our site, but as Ute noted each county's processing time is different. In some cases, we receive updates in a matter of a few weeks. In other cases, there can be a delay of a few months.