Cyms keep rotting

[DelawareJim]

I don't understand what I'm doing wrong here. I usually score a couple of regular Cyms in late fall early winter from my local orchid society raffle. I give them the coolest sunniest spot I have and keep them on the dry side until temps get above freezing when they go outside, usually May. I keep them under a honey locust tree that gives them dappled sun/partial shade all day. I continue to keep them on the dry side to reduce any chance of rot and they reliably start new growths and then some time in July they completely collapse to rot. All mature bulbs become an outer husk filled with water and the roots all got to mush. The undeveloped new shoots fall out of the pots and I through the whole mess away.

I don't have any problems at all with the few Asian Cyms I have.

So what am I doing wrong? It's driving me crazy. I'm thinking of putting one in straight LECA in a clay pot as soon as I get it just to see if I can get them through the summer.

Cheers.
Jim