Hi,I usually hang out in the brugmansia forum,but lurk here occasionally. I believe that what happened to your plant is that while it was still tightly rolled up in the p-stem,or just as it emerged,before it un-furelled,an insect,probably a beetle or a grasshopper among others,bit one hole in the leaf that went through a few layers of rolled up leaf.As the leaf unrolled the hole spread out,and it looks like a bunch of different bites,but it is all from the same bite. Sort of as if you rolled a piece of paper tightly,then took something and cut a small hole in it,then unrolled it,you would see a bunch of holes,all in a row,that looked like something ate it,but it was just 1 hole at first.Hope that makes some sort of sense to you,I know it sounds odd,but,I'll bet that's what happened.
Dan

ladybug, you don't say where you live in your GW Zone, but if you're in California, most likely this is snail damage. Very common here.

Patty S.

My zone is 9 Daytona Beach Florida

Space Aliens. Gotta be Space Aliens.

when you have holes in a perfect line like that is is usually a leafroller caterpillar. They get on cannas as well. just about anything with the big tropical type leaves