I learned that the issue was due to the triggertype 'RecordAfterSave' was only available in Summer 20 and my PROD instance was not an the summer 20 though its sandbox were upgraded earlier.
It has been resolved now by adding a 'release' parameter to my "project-scratch-def.json" file for creating a scratch ORG. Here is the example below.
{
"orgName": "My Scratch",
"release" :"preview",
"edition": "Developer",
"hasSampleData": false,
"features": [
"Communities",
"FieldService",
"LiveAgent"
]
}
Note: You might have to remove 'release' from son file once the Prod is upgraded to latest release version.