wrf.interplevel and wrf.vinterp results in very high values for vertical temperature gradients

Hello, I am trying to calculate the vertical temperature gradient between the surface and 1 km AGL.
I did the following:

temp2m= wrf.getvar(wrfnc,'T2') #wrfnc is the WRF output file for a specific hour
tk= wrf.getvar(wrfnc,'tk') # Temperature in Kelvin
height_agl= wrf.getvar(wrfnc,'height_agl') # Model Height for Mass Grid (AGL) in m
temp_1km = wrf.interplevel(tk, height_agl, 1000) # tempertaure interpolated to 1000 m above AGL

Then I caculate dthe temperature gradient between surace and 1 km AGL as follows:
del_T1= temp_1km-temp2m # kelvin
del_h1= 998 #1000 m- 2 m
Temp_gradient= -(del_T1/del_h1)*1000 # -dT/dz (K/km)

I am getting very high values for temperature gradient between surface and 1 km above ground level, and I am not sure if they are meteorologically correct. I have attached a screenshot of the values.

I also tried using wrf.vintep as follows:
temp_1km = wrf.vinterp(wrfnc, field=tk, vert_coord="ght_agl", interp_levels=[1], extrapolate=True,field_type="tk")
The document (https://wrf-python.readthedocs.io/en/main/user_api/generated/wrf.vinterp.html) says ’ght_agl’= grid point height agl [km], so I set the interp_levels as 1 km. But I similar results with slight difference.

Start by reproducing the reported interplevel and vinterp calculations from the issue, then read the linked wrf.vinterp documentation and compare the height and temperature inputs. Done means determining whether the high gradients are expected or identifying a specific interpolation defect and a reproducible correction path.