@VenkateswararaoK What is the pega version you are using ?

Bulk action works flawlessly in 24 and 25. Hope below is the setup you have at your end.

App Studio View Configuration

Optional Action Setup on the stage

Flow Action Configuration

Ensure that you have the local action properly set up in the specific stage where you want your users to work on the assignments in bulk. If the case is not on that assignment you will not see the flow action shown in the Bulk action button dropdown.

Even with the above setup if you are still facing the issue, you can delete the list view and create a new one. It might be one-off view generation/cache issue.

You can try creating the table using Insight as well through Explore Data landing page in App Studio and use it in your landing page as an alternative. That should also have the same outcome similar to list view.

Insight Configuration

Output

Let us know if you still face any issue.

Happy exploration!!!

Thanks

JC