configured pipeline to use github repo. Jenkinsfile is provided from source code. but that configuration is getting disappeared when we come next time, but it uses the required branch and jenkinsfile.
Jenkins version 2.375.3 running on kubernetes installed using heml chart
This is the same issue as the other one you reported, answer is the same GitHub Authentication reset after jenkins restart
disabled the configuration-as-code plugin and reinstalled github plugin, which solved the problem.