So far I've never seen it, too. I like such flowers a lot, looked it up and could find that there are two colourations within this species....a mor green(ish) one like yours and a more brown(ish) one.Never seen it! What a nice clear green.
Leslie, this could be affected by two reasons......too much orchids or beginning of senior moments. Both should give you pause. Think about this...... now if I could only remember where I put mine lol.