3D subtitles are a nightmare. If a movie lacks text, download .srt files and ensure your player renders them in front of the 3D layer, not inside the SBS image. Otherwise, you will see double text.
In a 3D SBS video, the frames for the left eye and the right eye are compressed horizontally and placed next to each other in a single 1080p or 4K frame. Index Of 3d Sbs
A "review" of the search term refers to the practice of using Google Dorks to find open directories containing Side-by-Side (SBS) 3D movie files. 3D subtitles are a nightmare