Ah, I understand what you mean now. In Kodi, playback of Live TV and Recordings are handled in separate manners. Live TV is treated as a constant stream, whereas a Recording (even a recording-in-progress) is seen as a separate video file. I personally have never used the "Start from beginning/play recording" option when selecting a program item from the EPG, but I imagine it would use the same player that it uses for Recordings, and playback would end it reached the end of the program, rather than continuing to stream the channel.
This is a limitation that is rooted in the fundamental architecture of Kodi, and cannot be resolved without restructuring.
It really is a shame that Kodi treats Live and Recorded content so differently, as it makes using Kodi as the HTPC interface more frustrating than one might imagine. However, until this dichotomy is resolved (and reading the posts about changes scheduled for Kodi v18, it won't be happening any time soon), the best advice I can offer to keep in mind that Live TV and Recordings are separate and different.
