I generated a new app with Phoenix 1.8.1, Kino 0.17.0, Elixir 1.19.0-rc.2 and Erlang 28.1. I don’t see any files recompiling during a request.
If someone has a minimal app where this happens with latest versions, I am happy to take a look.
Kino uses __mix_recompile__?, but it should definitely not return true without any changes (more specifically new modules using Kino.JS).
On a sidenote, I would generally recommend against depending on :kino in an app. When using Kino, instead of Attached mode, it’s best to use the default runtime and then execute code in the node using “Remote execution smart cell”, or just :erpc. This way the notebook can use arbitrary dependencies (Kino, all Kino* packages, and whatever else is needed).