If the top of the buds become glued together with a clear, honey-like substance, try misting the bulbs to dissolve this sugary secretion. They should open normally. Vandas in pots should be potted in coarse charcoal or bark as their roots require ample air. Repotting should be done every 2 years or as the root system expands above the pot. After repotting, keep the plant a bit on the dry side for the first couple of weeks as this allows any cracked roots to heal.
Vandas prefer clay pots as they breathe better than plastic.
If your plant is growing in a teak basket and you cannot keep it wet enough, simply tuck the root system, teak basket and all, into a new clay pot, and fill in with charcoal.