SysMLv2: It is permissible to use = binding shorthand from a parameter (redefining an inherited parameter) to a parameter that is inherited (without redefinition of the target) and vice versa

Here the vice versa case is atypical but permissible.

Typically, where an action has sub-actions, the = binding shorthand is used on a (necessarily redefining) parameter of the sub-action to bind to a "boundary" parameter of the owning action (the boundary parameter of which may or may not be redefined).

(Note that parameter "argument passing" syntax is just a form of redefinition.)

But it can be done the other way around; a typed owner action can redefine one of its parameters to bind to a parameter of an owned sub-action, which may or may not be a redefining parameter (redefining merely in order to provide a "clean" binding target).