In the last version, 1.1.1, the subtitles have layout issues, which can be seen here #3292 and has already been fixed in the version 2.4.0, in the PR #3323.
Today I use version 1.0.2 to not find the problem and hopefully they can update the Chart.js to the latest version.
Thank you
Step to reproduce
For the problem to occur, you need to use a version after 1.0.2. I do not know how to set the steps to play, but it will happen as the graphics are used.