New Cattleya Leaves Distorted

[Leisurely]

I am hoping that one of the Cattleya experts can diagnose my problem.

Accordian leaves on Oncidium types are indicitive of too little water. I am having something happen with my Cattleya leaves that I cannot diagnose. When the new growth starts, the sheathing material appears to be too snug for the leaf, resulting in the leaf having a vertical fold. The sheath has an opening, as you can see in the pictures, that allows water to enter and it sits there and causes a fungus problem resulting in black rot.

I have never had this problem before and I have not changed my watering practices. I water about once per week and the pseudobulbs are nice and plump. It seems that the leaf grows faster than the sheathing which causes it to wrinkle. I am hoping someone can give me some advice.

Thanks!