Steps to reproduce:

• emacs -Q
• load jupyter and ob-jupyter
• create a new buffer in org-mode
• insert the following and put point at |

#+begin_src jupyter-python :kernel python3 :session default
|
#+end_src

• M-x describe-key RET C-x C-e RET

Expected:
Documentation on jupyter-eval-line-or-region

Actual:
Documentation on eval-last-sexp

You can see the same issue with completion-at-point-functions. Start typing (from the org buffer) in the source block and look for completions. jupyter-org-interaction-mode is supposed to provide completions from the kernel, but it doesn't.