Editing a linked @import file from primary doesn't trickle to recompile

[replete]

Best explained with this .less snippet:

/* This file is app.less */

@import "reset.less";
@import "dependency.less";

html {
border:100px solid red}

@import "some-module.less"

Editing some-module.less (or any imported) triggers a refresh in the browser, but not a recompile of app.less.

Is there any way to force a recompile of everything? The only solution is to save some-module.less changes and then add a space to app.less - which isn't great.