What invokes Bootstrap overrides.css? I have a purchased theme that I've cloned, to which Bootstrap is set as the base theme.
I've done the standard rebranding procedure of renaming all of the files and functions to match the new theme name [theme2].
It's mostly working, except that /themes/bootstrap/css/overrides.css is loading in theme2, and its causing a few issues.
It doesn't load in the original theme1, and everything is fine.

It doesn't seem to matter if CDN is on or off.

What invokes Bootstrap overrides.css?

Any thoughts?
The default Drupal Bootstrap 3 subtheme has all the required LESS files, which includes the overrides.less file. This file, and all others, is rendered into the style.css file by the LESS processor HOWEVER this can change if your processor is wrongly configured, so make that the first thing to check. Then check that your theme .info file is only referencing the css/style.css file and not any other css files.

https://www.drupal.org/node/2052931