Yellowing Leaves

[scy]

I noticed some change in my cymbidium chen's ruby from last week. I am treating this orchid with malathion and a systemic, switching sprays each week, so it does not get used to the same spray. It does not seem the malathion is doing much other than drawing them out to the surface and I have backaches from cleaning each individual leaf. I think I will just stick with the systemic going forward.

For the past 2 weeks, I started to put it outside on the deck (east facing) in the morning hours only for more sunlight. Normally it sits by a deck door. Outside, the temperatures are 80s-90s, med humidity, dappled sunlight around 9 am but full sun from 10 am onwards. I bring it back inside at noon. I noticed that the leaves are not medium lush green as they were but started to turn light green, which I thought was ideal for cymbidiums. I noticed these brown spots on the leaves that weren't there last week. I cut them from the leaf. They were located in the middle of the leaf (lengthwise). Is this a result of sunburn?

The 2nd photo shows a few leaves yellowing. While I have removed 3 yellow leaves from May - June, I noticed there are 3 more yellowing leaves now. I did not panic too much before, because the original leaves were in the center, leading me to believe it was just from old growth. However, one of the leaves are from new growth while the other 2 are from the center. Also the yellowing progression is different from each other. One shows yellowing straight down the middle while the sides are green, while the left one is green at the base, then alternates between yellow and green along the leaf. Is this a result of scale or something else?

I have left it inside this week after noticing the changes. Also the photos are not accurate in terms of leaf color. I took them quickly on my phone and they are much lighter in person (med - light green). Thank you for your help!

Susan