As Alice said = Increase air movement around your slipper orchids. And remember, it takes slipper orchids a long time to heal. We had a fan go out two summers ago when the temperature was 100+ outside. The greenhouse got up over 140 degrees before I got a replacement fan. We lost lots of plants and my paphs suffered terribly. They are just now starting to look decent again. It takes a long time when they get damaged. Patience.

cheers,
BD