[gembud] 0.5 deg GFS GEMPAK files missing data along 0 meridian

I am using gptraj to run some stratospheric balloon forecast trajectories and 
have found that gptraj crashes because of missing data right along the 0 
meridian. The GRIB2 data (GFS 0.5 deg)  was obtained from NOMADS grib filter 
with the following bounding:

leftlon=0 rightlon=360 toplat=90 bottomlat=-90

I decoded the data with dcgrib2, with just dcgrib2 -m 99999 filename

gdinfo says this about the file:

GRID FILE: 2015022000_gfs003.gem                                                
                               

 GRID NAVIGATION: 
     PROJECTION:          CED                 
     ANGLES:                 0.0     0.0     0.0
     GRID SIZE:          720 361
     LL CORNER:             -90.00      0.00
     UR CORNER:              90.00     -0.50

 GRID ANALYSIS BLOCK: 
      UNKNOWN ANALYSIS TYPE 

 Number of grids in file:  1924

I have no data at 0:

 GEMPAK-GDPOINT>r
 
GDFILE: 2015022000_gfs003.gem                             
GPOINT: -45;0                                             
GVCORD: pres                                              
GLEVEL: 7                                                 
GFUNC : urel                                              
SCALE : 0                                                 
     150220/0000F012 :  -9999.00000

I do have data at 0.1 and -0.1

GDFILE: 2015022000_gfs003.gem                             
GPOINT: -45;0.1                                           
GVCORD: pres                                              
GLEVEL: 7                                                 
GFUNC : urel                                              
SCALE : 0                                                 
     150220/0000F012 :     -5.82000
 Parameters requested: GDATTIM,GDFILE,GLEVEL,GPOINT,GVCORD,GFUNC,SCALE.
 GEMPAK-GDPOINT>gpoint=-45;-0.1
 GEMPAK-GDPOINT>r
 
GDFILE: 2015022000_gfs003.gem                             
GPOINT: -45;-0.1                                          
GVCORD: pres                                              
GLEVEL: 7                                                 
GFUNC : urel                                              
SCALE : 0                                                 
     150220/0000F012 :     -5.80000
 Parameters requested: GDATTIM,GDFILE,GLEVEL,GPOINT,GVCORD,GFUNC,SCALE.
 GEMPAK-GDPOINT>

I am assuming the issue is with the decoding of the file, but I am at a loss to 
figure out how to fix that. Any ideas?

Thanks,
Robert Mullenax
CSBF Meteorology