Browser: Firefox
OS: Windows
This is a PSA announcement that if you suspect your CSS issues may have something to do with the Cascade Layer, and you ALSO have the Perfmatters plugin, to update to the latest version (2.5.1) and see if that resolves it.
I was still running into CSS conflicts with the Cascade layer enabled while on Perfmatters 2.5.0, but Jenn from Bricks was so helpful and suggested it could still be the plugin.
Solution: Update to Perfmatters 2.5.1 and see if that resolves your issue. Once I updated and cleared all of the cache (CSS, minified CSS/JS, etc.) and did a Hard Refresh 2x, the problems went away.
Hope this helps someone running into a similar conflict.