Great question! In California, there will typically be a fair amount of time between when a notice is due and when a lien claim would ultimately be due. CA preliminary notices are due within 20 days of first furnishing labor or materials to the project. They can be sent late, but late notice will only be partially effective.
As for the mechanics lien deadline, that deadline runs from the completion of the project - and the lien claimant will have 90 days from the completion of the project to file their mechanics lien. So, there will typically be more than 90 days between the time when a preliminary notice is sent from the deadline to file a lien.
However, depending on the circumstances, it's possible that the timeframes could line up to where a lien might be due relatively shortly after sending a preliminary notice.