I can't duplicate the problem. Can you provide more details about the steps that you took and the exact plugin versions that are installed on your Jenkins controller?

Steps that I took while attempting to duplicate the problem:

1. Install Jenkins 2.375 with the naginator plugin and many other plugins as described in my plugins.txt file
2. Define a freestyle project (job definition)
3. Add the post-build action to "Retry build after failure" and save the job definition
4. Open the job configuration page and confirm that the action is still defined on the job

My initial suspicion is that one of the installed plugins has a problem with the configuration form modernization that happened in Jenkins 2.277. However, that needs the precise list of plugins and their versions in order to test that theory.

markewaite Seems I missed one more point. Instead freestyle project, I created a "pipeline" project and looking for Post-Build action drop down. Is this plugin more suitable for freestyle projects?

Pipelines are best configured by modifying the Pipeline script rather than modifying the settings through additional plugins available from the job configuration page. That prepares the Pipeline job to store the definition in an SCM system and allow its definition to be managed as part of the SCM history of the repository that it is serving.

See "Timeouts, retries, and more" in the Jenkins Pipeline documentation for more details.