Leaf yellowing from Crown?
 

My phal is exhibiting some issues:
- It had significant root rot after repotting, which led me to go back in and remove rotted roots and repot again.
- a couple weeks later, the rotting has subsided and the existing roots are having nice healthy new roots forming.
- There has been a slowly yellowing leaf (bottommost leaf) which is yellowing normally starting from the tip.
- Recently the second bottommost leaf has started yellowing except it started at the crown. And this one yellowed much faster and is already more yellow than the bottommost one (which had a few week headstart in yellowing).

Any idea what is going on and whether this is cause for concern?

I inspected the roots and they are still ok and the new roots are growing nicely.

How many healthy roots do you have left? To loose the bottom two leaves in a season is not that abnormal - especially with compromised root systems.

i have about 4 healthy roots left.
is there anything suspicious in the way that the second leaf is dying (yellowing from crown and turning yellow REAL fast)?

There is always a concern when a leaf yellows from the inside toward the tip. This is likely pseudomonas infection and is common is phals with root issues.
Treatment of choice is Phyton 27.
This is the same bacteria that cause crown rot. The other is Erwinia which behaves very similarly.
The infection spreads quickly in both cases as you have described. Erwinia is also killed with Phyton 27.

yikes! is this a goner if i do not treat it? i just cut off the leaf and put cinnamon on it. The rest of the leaves look healthy. Also, i noticed more healthy root growth coming from the base.

For now, that's about as much as I would do...but the worry lingers :_(
So you watch and if things progress then :(

so far seems not to have infiltrated the other leaves. roots are in good shape and the original yellowing leaf is still yellowing slowly. crossing my fingers!