.fz fits files KeyError: "Keyword 'ZSIMPLE' not found in 0.3.2 versus 0.3

I have some .fz fits files that are giving the error:

KeyError: "Keyword 'ZSIMPLE' not found."

when I use astropy 0.3.2 and also 0.4rc3.dev9443 but 0.3 reads the header OK

The header looks like
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.
.
ZVAL2   =                    4 / bytes per pixel (1, 2, 4, or 8)                
EXTNAME = 'COMPRESSED_IMAGE'                                                    
ZSIMPLE =                    T / file does conform to FITS standard             
ZBITPIX =                  -32 / number of bits per data pixel  
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.
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