Missing LABEL TEXT attribute bind causes crash in shp2img

[geographika]

On MapServer 7.0.4, Windows x64 I am getting the following error / crash when using more than one iteration of shp2img, and referring to a field name that does not exist for LABEL text:

Unhandled exception thrown: write access violation.
msyystring_buffer was nullptr.

This occurs in mapfile.c - line 6751:

  msyystate = MS_TOKENIZE_FILE;
  msyylex(); /* sets things up, but doesn't process any tokens */

  msyyrestart(msyyin);  // crash here

Running one iteration of shp2img works:

shp2img -m test.map -c 1 -o test.png

Running two iterations causes a crash:

shp2img -m test.map -c 2 -o test.png

Test Mapfile below.

MAP    
    EXTENT 0 0 100 100
    SIZE 100 100
    LAYER
        TYPE POINT
        STATUS ON
        FEATURE
            POINTS
                50 50
            END
        END
        CLASS
            LABEL
                TEXT "[Missing]"
            END
        END
    END
END

[geographika]

Thanks @rouault