These LAS files contain synthetic points.  These points were generated by the Riegl processsing software to fill Multiple Time Around (MTA) zones, which are a physical
phenomenon that exists in any time of flight lidar system which has multiple pulses in air and wishes to record all of them seamlessly without range gate limitations.

The MTA zones only exist in narrow bands of ranges and typically are dependent on flight planning parameters and project area topography.  

Dewberry has maintained the synthetic point flag for these points and will document their existence and method of creation in the final report and metadata.