On June 27, 2024, a small number of users globally may have noticed that 1.1.1.1 was unreachable or degraded. The root cause was a mix of BGP (Border Gateway Protocol) hijacking and a route leak.
It's interesting that the internet is packed with search hits of complains that Cloudflare's DNS is slowing everything but Cloudflare representatives are quick to post followups pointing the finger everywhere else.