Diffuse brown spotting (unnatural) on psychopsis butterfly leaf

[Jopi]

Dear all,

I hope somebody can advise me on this.
Few days ago I have noticed that on my psychopsis there are diffuse brown spots. They look like if they have a black centre small spot and the brown goes around (photo). It is only on one leaf and I check my plants every morning. I have re-pot this plant like 10 days ago. It is in my windowsill and doing fine. It has a new flower bud forming and even keiki growing from one of the nodes.

Looking forward to hear some opinions and advices...

Thanks!

J.