I agree, looks like sun damage.
The leaf on the left, where the edge of the damage seems to be in a straight line across the leaf. And the leaf directly behind and above it was damaged too (looks like the edge of the leafe is gone). That looks like two hostas that I have on the east side of my house. In each case there is a window above and behind the hosta. The hostas next to them, that are in front of wall instead of window, are fine. But the ones by windows get scorched by morning REFLECTION, where the sun hits the window from above, which then reflects off the window down onto the hostas. Because it's distinct rays from the reflection, many of the spots look like that leaf on the left where there is a very distinct edge to the damage, and it's a straight line. I think the effect of the window is kind of like trying to start a fire with eyeglasses, the glass magnifies the sun as it reflects it. At least that's all I've been able to figure out. When I first noticed the damage, I thought it was a problem with the hosta, so I put a different hosta there, and the same thing would happen. So I finally figured it must be the location, not the hosta. I came up with this when I noticed the evening sun reflecting off the neighbors window, then it dawned on me that the same thing could be happening in the morning on my east windows. ......or maybe I'm just crazy, but this is the only thing that made sense to me.
