Field Update on a parent Module is not triggering the workflows

Field Update on a parent Module is not triggering the workflows

Situation:
Module Contacts
Workflow Contacts_A that is triggered on Field update

Module Introductions with a Lookup on Contacts
Workflow Introductions_B that is triggered on Field update

Workflow Introductions_B is set up for module Introductions that runs an Action that does Field Update, but that Field Update is for Contacts module.
 
Actual:
Field is updated on Contacts module , but workflow Contacts_A is not executing.

Expected:
Field is updated on Contacts module AND workflow Contacts_A is executed.

Can you please fix the bug?