I experience the same problem.
Many friends and family connect to my server using various devices and operating systems. Everyone with a (first generation) Chromecast is experiencing the appearing controls and playback halts. Playstation, NVIDIA SHIELD and Web playback is unaffected.
The relevant log file output during these issues is a repeat of these three lines
Oct 16, 2016 09:48:38.272 [4900] ERROR - Throttle: timed out trying to read chunk 65
Oct 16, 2016 09:49:01.841 [0584] ERROR - [Chromecast] [Subtitles] Request failed. [undefined] Count: 1
Oct 16, 2016 09:49:19.039 [2368] ERROR - handle_stream_read error 10053 An established connection was aborted by the software in your host machine