Cattleya leaves don't open...?

Possibly humidity...

 

I have had that happen with Cattleyas grown indoors compared to the greenhouse. My theory is either the lower humidity is causing it, or lack of water hitting the leaves. I started taking the ones grown in the house to the sink and spray the whole plant when I water it.

 

I have seen it only when they experience some stressful condition at a bad timing (e.g. when the new growths are pretty close to be fully opened). For example, the growth which is expanding during the shipping could stop the growth without opening the leaves, and start to make the next growth. Or they didn't get enough water (e.g during the travel) at a bad timing. Or a growth which started to grow in a wrong time of the year (e.g. shipped from Southern hemisphere to North). But since you haven't changed the culture, this is probably not the case.