Identify the text presentation you expect
Note whether the expected text is a selectable subtitle language, closed captions or wording already burned into the picture. An application cannot turn burned-in image text on and off as a separate track. Keep the actual file edition and language with the observation.
Apple says a movie without subtitles does not show an option to view them. Its separate closed-caption note names embedded CEA-608 format. The presence of a subtitle file beside a movie or a caption option on a streaming website should not automatically be treated as evidence about the tracks inside this local movie.
Inspect the relevant QuickTime control
For a movie that includes subtitles, Apple documents the language choices under View, Subtitles and through the playback controls. For supported embedded closed captions, it documents View, Show Closed Captioning. These are related controls with different availability conditions.
Compare the exact file with another known permitted sample whose relevant text is present. Record whether the option is absent, selectable but invisible, or showing an unexpected language. Those states concern different stages and should not all be reduced to captions being broken.
Keep track availability separate from styling
Changing text appearance cannot create a track that the movie does not contain or make an unsupported embedded caption presentation available. Establish the actual track first, then investigate readability or timing. A font change is an incomplete test when the original symptom is an absent control.
For help, provide the macOS version, movie edition, expected text type and the menu state for each sample. Include available media information without publishing a private file location. This allows a report to distinguish missing content, the specific CEA-608 caption boundary and a later display problem, while preserving the source file and avoiding broad preference resets.