Command object LazyMap databinding not working in grails 3.3.7

We have application running on grails 2.2.4/java 1.7 and we are upgrading to grails 3.3.7/java1.8. Running the application on grails 3.3.7 we are noticing in a particular case the parameters to command object databinding is not working, same code just runs fine in grails 2.2.4

I have created a repo in github with a sample app reproducing the issue , containing the codebase for both grails 2.2.4(data-binding works fine) and grails 3.3.7(data-binding issue, with error in command object).

GitHub repo URL is https://github.com/swzaidi/sample

I will also inline the HTTP request data and relevant code snippet from sample app for your quick reference.

HTTP Request data

student.id: 1000
courses[1000].course.id: 1000
courses[1001].course.id: 1001
class EnrollmentController {

def save(EnrollmentCommand cmd) {

println "+++++++ cmd has errors" + cmd.hasErrors()
println "+++++++ cmd errors " + cmd.errors

}

}
class EnrollmentCommand {

Student student
Map courses = MapUtils.lazyMap(
new HashMap(),
FactoryUtils.instantiateFactory( CourseCommand ) )
}

class CourseCommand {
Course course
}
DataBinding error in grails 3.3.7

Error in object 'student.EnrollmentCommand': codes []; arguments []; default message [No such property: course.id for class: student.CourseCommand
Possible solutions: course]
DataBinding works fine in grails 2.2.4. Please see the below screenshot

intellij debugger screenshot

I will appreciate any insight on this issue and any idea on how to resolve it will be great.

Thanks, Shiraz

### Environment Information

- **Operating System**: Linux
- **Grails Version:** 3.37
- **JDK Version:** java 1.8
- **Container Version (If Applicable):** TODO

### Example Application

GitHub repo URL is https://github.com/swzaidi/sample

Start with the linked sample repository and compare the Grails 2.2.4 and 3.3.7 versions, focusing on EnrollmentController, EnrollmentCommand, and CourseCommand. Reproduce the request with student.id and courses[1000].course.id, then investigate why Grails 3.3.7 reports “No such property: course.id”; done means the command object binds these nested map values without errors.

Written by the indexing model from the issue text.