leaf rusting on Paph Micranthum
 

Looks like a fungal, should I proceed with copper spray? I havent encounter this type of infection this much until this year.
thanks fully only one leaf.

https://imgur.com/HmDAOaT.jpeg
https://imgur.com/GHekCyZ.jpeg

I think it's more likely humidity, sunburn, high-mineral water or thermal injury. Also when you see brown patches on Paphs., always look for mites.