That looks like a bug problem. Pick a few leaves and look for bugs, caterpillars, tiny mites, etc. That said, most of the bugs are killed by the same stuff, so it doesn't make a big difference if you identify the culprit.

I have Woody living under my porch and his friend Chucky visiting. I've seen a porcupine and have a gazillion Chippies, white-footed mice, shrews, squirrels, although maybe the gray foxes are making inroads, I hope so. My sedums are doing fine. The basil I planted got munched to the ground overnight.

Slugs and/or caterpillars do this on mine. Always seems to be furry caterpillars I find on them.

This year the deer, who usually leave my sedums alone, have chomped them to bits along with my daylilies. Thankfully sedums are very tough and most have recovered and are now blooming.

is that sedum in full sun ... i would have expected a lot more of it in the second year after planting ..... im not even sure it looks like what i call autumn joy ... mine has much more pink flowers.. but that might be a camera / pic issue ....

regardless of what it looks like ... it is almost october.... it will be back .... keep an eye on it in late spring.. and find out what might be attacking it ...

ken

check for sawfly larva