SRT subtitles on Chromecast constistently disappear a few minutes before the movie end

I did not surrender on trying to fix this bug. I’ve enabled debug, saved the log files and isolated the minute where the issue happened, but could not find anything odd. No error, no messages that look out of order.
It is really sad that Plex Team believes that this issue was solved in version 1.10.1.4561 (from Dec’17), according to this forum thread, but has been reported again and again, as seen here (Aug’19) and here (Nov’19). Plex developers, nobody is curious about solving this? I would be.