Came home from a ten day vacation and found that the seedlings I planted out before I left have new growth that is severely stunted and shrivelled. Very tiny leaf stubs, like 1/8", sort of reddish perhaps, some of them kind of dry and curled. Hard to describe or take a photo of. The older growth seems fine, the leaves just below the afflicted parts are a bit mottled light green.

Doesn't seem to match common viral diseases I've found images of. I think these are Black Cherry. Though they could be Cherokee Purple, apparently didn't label them..

I planted five out, of two varieties. The other three of one variety are fine (and not as tall) but these two of the other both have this problem. They may have been a bit short on water though everything else looks fine.

Any advice appreciated. Is it possible this is some sort of drought stress or too much sun issue? It has been fairly hot consistently. Or almost certainly disease?