Yellow Phalaenopsis Leaves...Age or Sickness?

[Plantcrazed101]

My Phalaenopsis NOID just started growing what looks like either a root or spike, but it also yellowed a few of its bottom leaves...is this normal or should I be concerned that it has an issue? I haven't really changed care for it very much, although it is overdue for a repotting. What do y'all think?

[Plantcrazed101]

and here is one more photo of the same plant:

[Brooke]

To me that looks like typical leaf loss on the oldest leaf. It will continue to turn yellow until it falls off.

Brooke

[The Mutant]

Did both of them suddenly start to turn yellow at the same time? I've learned that if a Phals starts losing several leaves all of a sudden, and quite rapidly; there's usually something bad happening below the surface of the substrate.

If not, I would say it's normal and nothing to worry about.