astropy.wcs returns nan when galactic longitude >= 180 degrees

astropy.wcs returns nans if the cube contains pixels beyond 180 degrees. 

For example, with the following header:

SIMPLE  =                    T / Fits standard
BITPIX  =                   16 / Bits per pixel 
NAXIS   =                    3 / Number of axes 
NAXIS1  =                  256 / Axis length
NAXIS2  =                  256 / Axis length 
NAXIS3  =                 1024 / Axis length
EXTEND  =                    F / File may contain extensions
CTYPE3  = 'VELO-LSR'           /
CRVAL3  =                  0.0 / M/S
CRPIX3  =                512.5
CTYPE1  = 'GLON-CAR'           /
CRVAL1  =                  0.0 / DEGREES
CRPIX1  =              30977.0 
CTYPE2  = 'GLAT-CAR'           / 
CRVAL2  =                  0.0 / DEGREES
CRPIX2  =                305.0 
CDELT1  =             -0.00625 / DEGREES 
CDELT2  =              0.00625 / DEGREES
CDELT3  =     127.000209090909 / M/S

the commands:

wcs=astropy.wcs.WCS(header.copy())
wcs.wcs_pix2world([[0,0,0]],0)

returns:

array([[ nan,  nan,  nan]])

when it should return:

array([193.6,-1.9,-64.96]])