leaf vertical splits

[early]

Most of my 35+ plants are Phals and 95% are doing well.
I have one non bloomer that I notice a week or so ago had a leaf that has a vertical split midline. Today I noticed 5 leaf splits. I isolated her.

She has had the same watering and light as all the others. same weak/weekly of 20 20 20. most all are in a nearby east, window, and those not nearby are about 4 feet away but gets indirect light both from the east window and some from a north one.
I have been growing about 3: years, and somehow my few at first grew to over 35, with some Oncs and a couple of yearling vandas that are growing very slow and after a yr or two have not spiked yet, however the vandas still seem healthy in the east window. When I remember I about twice a month double the weakly weak watering. All my plants except a babied no root Onc with division of three rootless pseudobulbs. the mother one is adding new roots in LECA with sphagnum on top.
Thanks to all for critiques and suggestions

a ps all are in LECA solely. except three divided pseudobulb are just sitting in moss as suggested by EC who lives in an arid climate, he in Arizona and I am in 5000+feet New Mexico.