Dracula Psittacina black spots

[Manu]

Hello everyone

I purchased 2 Dracula orchids from Ecuagenera a few months ago at our local show here in Montreal. Both plants sit a few cm apart and get the exact same treatment, however the Psittacina has a bunch of black and brown spots on the leaves, attached pictures. Other then that it seems to be doing fine and has a bunch of new growths...

When I got it it didn't have any spots apart from black tips on a few leaves which I cut off when I potted it. I water them every few days and never let it go dry. I use regular tap water even though I know it's not ideal (the Bella gets the same treatment and has no issues) with very low fertilizer about once or twice a month. They get misted daily unless I'm away at the cottage...

The spots look like what I have on my Colmanara or Oncidiums which I know is normal for them but never heard of such issues with Draculas...

So I'm wondering what those spots are (fungus, burn, etc), the cause and the solution??

Oh and btw, the new growths do not have any of those marks.

Thanks in advance
Emmanuel