Strange Caching issue

Hi team

I have strange issue with reverse proxy configuration. I'm using reverse proxy configuration due to SSL from sha1 to sha256 transformation with proxy pass configuration

"proxy_pass https://abc.mydomain.com/;"

When we update the abc.mydomain.com dns record, nginx still resolve old ip address until it's restarted.

But Operating System resolving new ip address.

What may cause this issue ? it looks ssl session caching issue but i'm not sure.

Here is session configs

ssl_session_cache builtin:1000 shared:SSL:10m;

Thank you.