Is this a fungus? Looks burnt, doesn't grow [Pics]

[TENroaches]

I've had VFTs for a few years now, and I know about how they get burnt-looking if you rescue one from Lowe's and throw it in the sun, and they always come back making leaves that tolerate the sun. But I have VFTs that look burnt on flower stalks, and one looks burnt on every leaf. They've been outside for months, and other VFTs are doing great.

 

[hcarlton]

I'd probably guess sunburn. My plants get this throughout summer unfortunately, as temps rise and humidity drops.