I have been using the LIDAR .laz data for several months.  I have found that it is susceptible to transmission errors.  Sometimes, I have had 3 out of 4 files which were transmitted that were corrupted.  I use las2txt.exe to transform the laz data files to xyz triplets. After 'gridding' the xyz data...the resulting maps were corrupted up to 75% of their coverage.
At first, I thought that the original LIDAR data files might have been corrupt or that las2txt was generating errors.  But after running las2txt over several additional files and
it translated the data perfectly...I knew that las2txt was running correctly!
I then had the files retransmitted to me...this time the translation...gridding...mapping worked as it should.  Looking at the first transmission file size compared to the second try...the files were of different sizes.
So, if you get what appears to be bad LIDAR maps. Go back and have the same files downloaded to your site and try again.
The file sizes were nearly the same, so you won't be able to tell if there is a problem until you look at the finished map.