Try using another color sampling tool like the text paragraph tool to sample the green color then open the swatch picker and copy the color value and paste it into the swatch of keylight and does that get the right color.
Perhaps you could export a frame and open in photoshop then sample the color and paste the value as described above if needed.
This is a weird problem that may have to do with color profiles specific to your format, which i’m not totally familiar with so…
Let me know what happens. curious.
Andrew