Syslog full of "source ID not found"
Gnome Subtitles fills syslog with error messages like the following. There are thousands of consecutive lines like that.
Aug 7 01:06:29 my-laptop gnome-subtitles: Source ID 242534 was not found when attempting to remove it
What I expected: Have a sensible number of syslog messages from the program. What I got instead: Syslog full of source ID not found messages.
I used the newest Ubuntu PPA version of Gnome Subtitles as of 2018-08-06. I run Ubuntu 18.04.1.