Phal leaves turned to mush

[Bradfo69]

Haven't found anything in my books referencing this one. I have a large phal that was given to me and is probably the big box store variety. Two plants in the pot, leaf span nearly 2 feet and probably with some amablis in the parentage. On the whole it's been healthy but recently a couple leaves have (within days) have lost all cell structure and turned to liquified floppy mush (starting at mid leaf). No withering, yellowing or apparent cause. I repotted last week with fresh commercial mix and the roots all looked healthy with no evidence of pot bound pests. It hasn't been overwatered and hasn't changed position for 8 months. No exposure to drastic temp changes or humidity changes. (In the dining room, 72-83 degrees, open windows 6 feet away so relative humidity has been o.k.) No bright sunlight whatsoever. Nothing that would blatently trigger such a reaction. I had a new leaf about 2" long coming from the crown and the leaf below it was one of the leaves that became dessicated. I even trimmed it back to the green rigid healthy looking leaf base before the watery infected part reached it and it still continued and I lost the crown. The other plant in the pot is fine but the roots are so inter-twined I doubt I can separate them.

With a couple hundred orchid plants, the loss of this one is no big deal but, having never seen this, am looking for others experience as to what might be the cause. (There are still 4 large leaves below the crown that haven't begun to deteriorate but, I feel it's eventually inevitable.) I've lost phals in my time but the way this one has acted is totally foreign to me.

[Gin]

Hi , Water might of been trapped in the lower leaf junctions creating a bacterial rot that travels in the plants system . What I do is pour straight 3 percent peroxcide on the rot , after it is done fizzing wick it out as it reverts back to water . It will probably produce a basal keiki ... long wait Know how it is ... Gin