Red dot added when the css is set to compressed.

The plug-in works fine when it's set to nested, but as you can see on the left hand panel, there is a small red dot before all of the compiled css which is stopping the all selector from working.

Seems to be a zero-width no break space, found from here: https://apps.timwhitlock.info/unicode/inspect?s=%EF%BB%BF

Brackets shows it as a red dot. Any idea why this is being compiled into my css?

This is the beginning of my scss file:

I've now found that this disappears if I export the css into its own folder, so I'll use this as a workaround for now.