I get a notice and warning.

Notice: Undefined index: selectors in [...]/web/app/plugins/elementor/includes/css-file/css-file.php on line 132
Warning: Invalid argument supplied for foreach() in [...]/web/app/plugins/elementor/includes/css-file/css-file.php on line 132

Steps to reproduce

It happenes somewhat randomly. Might be after visiting pages after a template has been saved. But since its not always that way hard to tell. On refresh it disappears.

Workaround

Check if selectors index is set if not bypass loop.

Environment

Version 1.4.9, 1.4.10 and 1.5.1.