I have a noID dendrobium nobile which is producing two new growths (or a new growth and a keiki?) and one of them is getting some strange swelling. Does anyone know what it is? I got this one from my grandparents, so I'm eager to keep it alive and healthy
I took a closer look again at your photo. You're talking about the swelling in the stem of the newest growth that's developing above the height of the potting mix. Correct? Can't say for certain, sometimes aberrant growth just occurs and does no harm to the plant.
To avoid confusion about what you're asking, some photo editing programs will allow you to circle or draw an arrow to the object in question.
Today I noticed that there is another swelling at the base of the newly forming leaf of the new growth (see pictures). I am still quite confused about this, but so far it doesn't seem to hamper the orchid's growth.