Yellowing leaves mid-stem on a Vanda orchid
 

Hi! I bought a Vanda orchid 4 weeks ago. It was in full bloom until about 2 weeks ago. After i cut the spike off, i saw yellowing of the 2 leaves opposite where the spike was. This went on for about a week. Now, i see some browning at the base of the leaves where the yellowing started. I don't know what's causing this. Is this dehydration?

Water: I used to soak my Vanda about 15 mins a day but about a week ago, I switched to showering it for about 15 mins daily + misting in the afternoon, as i find soaking a bit tedious.

Light: i have my Vanda hanging by a south-west facing window sill. I leave the shades open all the time.

Temperature: 22°C at night and about 24-29°C during the day.

Humidity: usually abouy 80% unless it rains. It's the rainy season now so it rains about 1-2x a week.

Photos:
1. In bloom - June 25, as soon as I brought him home from the shop
2. Not in bloom - taken this morning.

Hope someone can help me out! I don't want to lose him.