In Comet Cache v160917 we included the Clear Cache button in the Admin Toolbar for the Lite version of Comet Cache (previously this was a Pro-only feature). As part of that work, the Chart.js was unnecessarily allowed to be included in the Lite verison here and here — this is unncessary as Chart.js is only used by the Comet Cache Stats/Charts feature (still a Pro-only feature).

We should avoid enqueueing Chart.js in the Lite version not only because it's not being used but because it can cause problems with other plugins that might be using a different version of Chart.js, as seen in the report below.

Pär Thernström, plugin author for the Simple History plugin (30k+ active installs) says:

Comet Cache uses an older version of the chart.js-library and there is a conflict because of the newer version included in Simple History. This will be fixed in the next version by putting the script used by Simple History in its own namespace.

Note that this has also been cross-referenced on the Comet Cache support forum.