Cym Flower spike died

[mikel6331]

A month ago I purchased a vibrant cumbidium with lots of blooms. Two spikes of new buds have died in the last week. What would cause this? I live near Vancouver BC and we have had temperatures below freezing outside which caused very low humidity 25 - 40% range, but the room temperature is 60 - 70 daytime and 50 - 60 nighttime. Normal humidity is 35 - 50%. The room is quite bright (lots of skylight and window), but very little direct sunlight on the plants.