Git SCM Polling is not working after System patch and Plugin Upgrade

Jenkins Polling SCM is not working as expected.

Jenkins Version: 2.414.1
Java Version: 11.0.20

Jenkins is Installed on Amazon Linux 2 machine. Earlier Polling was working fine until we update the system(machine). After that polling happens randomly. In the Poll SCM Log it shows the updated time, but with no changes. thats not True, We committed changes to the git repository. Only one time it is working fine. rest of the time polling is happening but it is not detecting changes.

PS: We are on a private subnet. we can not use the GitHub Hook. Any Suggestions to Overcome this?