Fungus? or something else?
 

Plant affected is Cattleya skinerii x Lc Angel Love, and it's this year's new growths that are affected. This first was noticeable when new growths were young; appeared as a slight reddish blush - I thought it was just from bright light on new growth.

But now, the reddish areas on some leaves have become slightly brownish-red and a bit sunken (on the worst affected leaf). There are growths where one leaf looks ok, but the other has some reddish streaks or discoloration. One leaf has a subtle, odd shaped lesion. I have perused the orchid disease page at St Augustine OS website - not sure that I see this ...

Pbulbs are firm, and look good; the older growths look good so far ...

I've had this about 6 years; no change in culture ...

Anybody have an idea what may be causing this? Treatment, if that's possible?

Thanks!

With the exception of the last pic, they still look like sunburn. Localized dehydration due to heat.

You know the routine, isolate and watch for spreading. ;)

---------- Post added at 06:24 PM ---------- Previous post was at 06:20 PM ----------

I should also ask, none of those areas are wet, right?

being young the new growths may not have been able to tolerate the same light levels as the older leaves...I sometimes stake up the young uns and turn them away from the light if thats at all possible..But I think sunburn too. Its doesnt look to biological or viral bec its too random IMO.. ;)

Thanks you guys :) I had been thinking it was sunburn, but when watering this week, that one very bad patch just doesn't look like burn I've gotten on other plants (unfortunately, I have a fair amount of experience with sunburned plants) :p
But, I think you may be right - might look different due to growths having been young, and more tender...

Thanks for putting my mind at ease! :)

I am not convinced of sunburn, especially when looking at pic1, 5 and 6. Watch it and when it is spreading, cut it away with a single use razor blade.

Yeah, those were the ones that most concerned me.
I'll definitely watch it!

I'm wondering…

The last looks like something spreads inside, I'd cut largely.

I wonder if something has not taken the opportunity of the burns to enter. The first pic has what could be lines of progression, which could be fungal.

I'd look closely for any sign of something watery or smelly. A smell would be helpful.

Isolate and look closely…