Look at the flower. It has 5 segments plus the lip. The lip is a modified petal and sometimes

something goes wrong and the pattern or the shape of the lip gets transferred to the petals.

Here is an example where the mutation was used in further breeding.

Peloric feature on Cattleya intermedia

Why has this happened on your orchid? Do not know! Unstable genes. virus??

I am totally guessing...no not virus. The plant looks healthy, maybe banged up from the past. I would wait a year to see how the flowers look. Keep it away from your other plants if you are worried.

Arthur is right, the plant seems Peloric and that would explain the odd pattern on the flowers.

Good luck,

Jane

Yes, the patterns are similar to the pattern/ colour on the lip. It affects only some of the flowers. Thanks, that is so interesting!! Was not at all aware of this possibility. Will wait and see then.

Many thanks Arthur and Jane.