Likely cause is bacterial rot which can happen when the plants are stressed (too hot, too humid or too wet). Removing all affected leaves. Relocate orchid to better air circulation, lower humidity and temp between 20-26 degrees.
This is nothing to worry about, it normally means that your orchid is thirsty. Immerse the whole pot in water for 20/30 seconds then leave to drain fully.
Correctly watered roots should be a healthy green colour, white or grey roots are lacking moisture..
As hard as we try to keep the plants secure, sometimes we cannot control a bit of travel damage. Nothing to worry about, just scoop it out of the box and add back to the orchid pot.