Freakish *bubble* on leaf of healthy Vanda coerulea!

[beanluc]

Hi, I got this Vanda coerulea last September. It seems healthy, it's growing even though it's the middle of the winter, but it developed a weird discolored swelling on one leaf!

The blemish appeared a month after I brought it home. It grew for a few weeks and stopped. So it's been there, unchanging, for more than 2 months now.

Anybody know what it's all about?

The swollen area is discolored - almost bleached or something, except it's gray instead of yellow. The very edges of the swelling are a little black. This is under the cuticle, it's not some mildew or such, growing on the surface.

That's the main thing I want to know about. But while we're at it, the same plant had a black spot low on the stem when I got it. Looks like maybe old water damage or something? The spot hasn't grown or spread since I've had it. Any ideas?

Thanks! Here are pictures