I just had new quartz countertops installed in my kitchen, including on my massive 8'x4.5' island. While cleaning them today, I noticed these strange chemical bleach-like streaks or drips that run down a significant portion (more than what is shown in the photos attached). They are very noticeable when the light hits. I can only assume these came from the manufacturing or fabrication step? I have tried buffing these markings out using a microfiber cloth with Granite Gold Daily Cleaner (labeled safe for quartz) and with mild soap and water. Neither of these made any improvement.

Is there anything else that can be done or is this permanent?!