Hi,
Got the root cause of the problem.
Here is the explanation:
The plugin was registered on the 'Pre-Operation' and in the code, I was checking the depth of the context object. So, plugin was returning when the depth > 1 and since I was creating the phone call records through quick campaign, the plugin code was returning
at the beginning due to "context.depth". Commented the depth code and the plugin is executing properly and the 2 custom fields are now getting updated as expected.
Thanks,
Abhi