A different kind of dendrobium leaf problem

[dannyeverlife]

Okay so I haven't heard of this happening but I wanted to ask. I believe I have a Burana Sunshine and it of course... has a leaf problem. There are three stalks; one shrivled and older with four leaves, one that is also older but very tall, and then a new stalk that is growing beautifully. The tallest and most previously bloomed stalk has begun losing it's leaves but the other two look wonderful. Is this just a natural thing for only one stalk to be losing leaves? I will admit I've never had a den with many stalks but I just wanted some advice.

Thank you!
Danny