As with anything in orchid growing there is a wide range of opinions and experiences. Any time you repot plants in bloom there is the possibility of losing the flowers early, but it may or may not happen depending on the situation. I personally avoid repotting plants in bloom unless the life of the plant is in jeopardy. If there is a choice of losing the plant or losing the flowers, I would repot the plant to save it. I had a Catt last year that was in sheath, but roots were really bad when I got it. You can read what happened here:
In general, Paphs seem to be really tolerant of repotting even in spike. I have one that was received bare root as a bonus plant and had a bud almost ready to open. I went ahead and potted it up and the bud opened without blasting. I was quite surprised. If you expect the worst and it doesn't happen
then things are extra good .