not sure why that is happening to yours ( draft, too dry, needs repotting, temps too high etc ) but I always recommend placing them outdoors during Summer and some of Fall - in dappled shade. They love it. Try it if you can.
With yours- you obviously are able to get it to set a spike. There must be some environmental change taking place afterwards that is causing bud blast. I hope you don't mist the leaves or spike, or anything like that..
The Zygo is on an open west window getting quasi direct sun from 16-20. It seems it did not mind the heat or strength, but a cattleya got a case of the burns.