This error code is in the process of being deprecated. You will begin seeing this error split between Missing Content - Conversation Event & Missing Content - Narrative Text Event for specificity.
Requires Forced Narrative
Certain lines, text, or scenes require translation in order for the audience to understand the plot.
This error code is exclusively issued against Secondary Audio assets. It indicates that during QC it was determined that on-screen text or dialogue needs to be translated within a Forced Subtitle file for that particular language.
You should not encounter a Redelivery Request for a Secondary Audio asset where this is the only error code listed.
If however you see this error listed against a Secondary Audio asset which has multiple errors listed then you can ignore the "Requires Forced Narrative" issue and address the other errors instead.