It's not a plant I know well, but that's good background info for those who might be able to help, to have.
Even though I make efforts to avoid it, when I take plants outside that have been inside for winter, there's usually some issues with sunburn on some of them. Some of it is similar looking to your plants' issue, but not identical. If others don't think that's what it is, I'll be going along with them.
Mostly just wanted to say Hi since u are new. ;)