I had some well rooted black raspberry canes that arched over and rooted at the tips. I cut a few and transplanted them.
One is apparently attempting to push a new primocane NOW. On September 29! Will that ruin it for next season or not really matter much?
Doesn’t matter much; will not amount to a lot in remainder of 2021 growing season.
The new growth may resume next spring; more likely that transplant will put up other protocane growth next spring. The new growth may also freeze out overwinter, but if the whole transplant is heavily mulched or snowed over, it should overwinter well.