Your phalaenopsis still looks good to me. But new leaves are getting smaller which shows your phal receiving less light than before. Pls move it to a place where it can get more sunlight. Morning sunlight till 11am is good enough. Afternoon sunlight is not good for orchids.

You can spray some fungicide solution to affected area. Or better slice off those affected area & apply some fungicide paste.

Do you pot it in bark mix? Look like your potting medium keeps has depleted. Watch out for it & check the roots.
If it stays wet for too long then it is the time to change potting medium. If not it will lead to root rot.

Good luck & all the best.

This is duplicate thread. Pls find my reply in other thread.