Lidar to Topography

Hi All, 

I have nominal 50cm classified lidar data, but upon import of the tif into leapfrog geo as an elevation grid, the smallest triangle size that leapfrog will allow is 3.84. 

I have the original las data and can confirm that the point density is in fact higher then 50cm. I did not produce the tif myself, so cannot confirm how it was made, but the vendor assures me that it is 50cm data. 

Is there some possible limitation or problem with leapfrog, or should I go about remaking the tif or dem?