Plant has developed a deficiency, what is this?

[optical]

Hi all, one of my plants has developed this problem but others are unaffected, just curious if you have any idea what's going on? I am losing the big fan leaves because of this now

Thanks kindly

 

[Imzzaudae]

This is Calcium deficiency.
Are you in Coco? If not what medium is she planted in and what you feeding her.
Do you P.H your water and your fertilizer solutions?
Please fill me in as best you can.