Error visualizing lowest levels of data

Hello, I'm using VAPOR to visualize output from CM1 simulations. I can confirm that I have data at z = 25 m, my first model vertical grid level. However, when I try to create a contour plot for, say, reflectivity at z = 25 m, no data plots. In fact, my reflectivity will not plot until I do so for my third vertical level (z = 125 m). As for the "region" I set for my VAPOR analyses: it is centered on z = 500 m and is 1 km in vertical depth. Not sure if it's related or not as I've had the above issue previously and did not have the following error message pop up, but this error sometimes pops up when trying to plot other variables at z = 25 m (or variables at certain timesteps): "Session Save Error 1, creating Data Manager: Failed to read region from variable/timestep/level/lod (zvort, 72, 0, 0)" Any tips are very much appreciated! Not sure if I'm missing some trick/setting or if this issue is indicative of some problem in my creation of my VAPOR input files? Thanks so much! Best, Alicia