Closed Captions missing when converting from mp4 to ts
The subtitles in the MP4 is a mov_text (tx3g) stream which isn't supported in MPEG-TS.

MPEG-TS support either DVD subtitles or DVB teletext. The former is a bitmap subtitle format and ffmpeg can't convert text to bitmap. FFmpeg has no encoder for the latter. Your best bet is to burn the subtitles but this means re-encoding the video.

ffmpeg -i in.mp4 -vf subtitles=in.mp4 -c:v libx264 -c:a copy out.ts