Event Duration Short
Duration that Timed Text events are visible on-screen is too short. There is not enough time to comfortably read the event.
Extend the duration of the event so that a viewer can comfortably read it in its entirety.
For scenes where there is a lot of quickly spoken dialogue, a small sacrifice in sync is acceptable to allow for a better reading speed. An events out-point can safely be extended up to 12 frames beyond the audio being covered by the event. Any more than that and you risk the file being failed for sync issues.
If you are unsure how to correct the issue without negatively impacting the overall sync of the asset, please contact your Netflix representative via Backlot.