Oncidium Buds not opening

[Welfkoondo]

Help please - I'm a fairly experienced grower although only 3-5 years w/ Oncidium Intergenerics. Over the last few months my Intergeneric buds have stopped opening. I see several things:
1) Several petals will open but not all,
2) Buds never fully develop or open (pictures attached), or
3) Spikes turn yellow and dry up.

This is even happening with some of my "old reliables" which have never struggled before. One of them had already opened 4-5 spikes successfully then started doing this. I recently had a Paph also do this - bud got very large then wouldn't open and turned brown.

Any ideas?

Thanks!
Welfkoondo

[estación seca]

You don't say where you are. This can be caused by being too cold, too hot, not having enough humidity or water, or being moved to a substantially different environment.

[Welfkoondo]

Thanks Estacion:

I live in NC. I have a small greenhouse and a large light array in my basement. I usually wait til they spike in the greenhouse then move them under lights so they can get more consistent light. (my greenhouse gets lots of shade in the winter due to Sun's angle). It's always worked in the past.

thanks again................