Nothing particularly odd there. Personally I'd do the @ with the subscribe call.

What you describe has happened to me in situations where callbacks are involved in rendering.

The important thing for reagent to work is that the line-chart call is invoked and before it returns all r/atom's it should watch are dereferenced.

Small nit... the clj->js is probably not needed because you're using [:> which does clj->js for you.