

Something that can make troubleshooting DNS issues a real pain is that there can be a lot of caching at multiple levels. Each DNS server can do caching, the OS will do caching (nscd), the browsers do caching, etc. Flushing all those caches can be a real nightmare. I had issues recently with nscd causing issues kinda like what you’re seeing. You may or may not have it installed but purging it if it is may help.
Sounds like you bookmarked the while flippin’ Internet.