There is a sticky substance on one if the orchid leaves. Clear bubble like What is this and can it be treated
Certified GKH Gardening Expert
Although finding this sap on your Orchids is a sign of good health, yes, it has the potential to cause problems if not cleaned off right away. If left alone, it may lead to a bacterial infection. Be sure to check the area for small round spots, which could be an indication of Scale, or even Aphids, sucking insects that produce same type of sap, that must be treated immediately.
A piece of gauze, paper towel, Q-Tip or tissue dipped in warm water does the job of removing the sticky droplets from the leaves.