My Heritage raspberry plant was seemingly doing well until this morning/afternoon, now looks like this:

https://imgur.com/a/s87bFSw

https://imgur.com/a/K6OL4k2

They are planted in a 50/50 mix of peat and miracle grow soil. We recently had some prolonged and intense periods of sun/heat so I was thinking drought/sun damage but could also be borer damage or potassium deficiency.

Thoughts?

Thanks!