to me it looks like there has not been enough water,fertilizer maybe warmth and I am unable to tell about the light.I find that these plants Love the warmth and the high 70's to the high 80's is about their ideal growing and flowering temps for the day and going down to about 65 at night.With these nice temps keep the humidity high,and I mean high - 80 - 90 % during most of the time.
Feeding they are a hungry plant,feed very well,I'm using a 20-15-15 with added nitrogen and magnesium twice a week at full strenght.The light levels for Sharry Baby is rather low for Oncidiums about 8000 - 10000 lux.