| Sometimes nurseries fertilize pretty heavily, understandable because customers like to buy big healthy plants. That's not a criticism, just an observation. My limited experience (only about 10 years of growing, compared with some here on the forum who have grown for 20-30 years) suggests that being prone to bacterial problems or other orchid diseases probably has more to do with culture than with any inherent resistance to bacterial infections. Strong plants stay healthy, weak plants get sick. I had a Broughtonia species in my collection years ago (got rid of it when I moved) and it grew and bloomed in a manner very similar to cattleyatonia hybrids.
If roots are healthy, I'd suspect nursery over fertilizing or getting too dry as the culprit. I'd repot at the appropriate time and lay off the fertilizer for a while, and then if I fertilized, I'd do it lightly.
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