Different last-modified response header values

Some of my users are receiving different (old) last-modified date for my text/html response. A few users reported that our site is broken in their browsers. When we checked their browsers, we found that cloudflare is serving old index.html. How it is possible that cloudflare will serve different versions of files to different users. Most of the users doesn’t have this issue. Cloudflare is sharing the latest version with them.

One more question to add with that, to do some testings I tried to disable CDN by clicking that cloud icon. Now the cloud icon is turned off (grey color) in interface. But even after 15mins, I’m still getting response from cloudflare CDN. How long will it take cloudflare to really disable CDN after turning it off from interface?

HTML isn’t cached by default at Cloudflare. Do you have a Page Rule that overrides this? If so, what are all the settings you’re using in that Page Rule?

DNS entries set to :orange: have a 5 minute TTL. If you’re still reaching Cloudflare after 5 minutes, DNS somewhere near you is not refreshing as often as it should.

EDIT: I see there’s a DNS issue at the moment that coincides with the timing of your post:
https://www.cloudflarestatus.com/incidents/2cwz2r8fb328