I’ve done research on behaviour of handlers together with include/import role.
https://medium.com/@george.shuklin/include-role-import-role-and-handlers-in-ansible-b32a5386a555
Short excerpt:
import_role
: All handlers are in the same scope, inner handlers always win.
include_role
: Handlers in an inner role are invisible for an outer role. outer role’s handlers supersede inner role’s handlers for tasks in the inner role.
Any critique/refinements are welcomed.