Whenever I turn on ipv6 on my router (isp supports it, dual stack) randomly I get half the download speeds, YouTube video freezes, and eventually a captcha scre

Whenever I turn on ipv6 on my router (isp supports it, dual stack) randomly I get half the download speeds, YouTube video freezes, and eventually a captcha screen on google. The moment I disable v6 even only at the client side I get to max out my bandwidth. Tested on google drive, sites on azure and aws and netflix’s fast.com which show’s your ip just to confirm I was connecting over v6.