Can someone help with this error?

App Versions

{
	"education": "15.5.0",
	"erpnext": "16.0.0-dev",
	"frappe": "16.0.0-dev",
	"payments": "0.0.1"
}

Route

Form/Student Applicant/EDU-APP-2025-00001

Traceback

Traceback (most recent call last):
  File "apps/frappe/frappe/app.py", line 116, in application
    response = frappe.api.handle(request)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/api/__init__.py", line 49, in handle
    data = endpoint(**arguments)
           ^^^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/api/v1.py", line 36, in handle_rpc_call
    return frappe.handler.handle()
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/handler.py", line 51, in handle
    data = execute_cmd(cmd)
           ^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/handler.py", line 87, in execute_cmd
    return frappe.call(method, **frappe.form_dict)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/__init__.py", line 1715, in call
    return fn(*args, **newargs)
           ^^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/utils/typing_validations.py", line 32, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/model/mapper.py", line 37, in make_mapped_doc
    return method(source_name)
           ^^^^^^^^^^^^^^^^^^^
  File "apps/frappe/frappe/utils/typing_validations.py", line 32, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "apps/education/education/education/api.py", line 50, in enroll_student
    student.save()
  File "apps/frappe/frappe/model/document.py", line 122, in wrapper
    raise frappe.DatabaseModificationError(error_msg)
frappe.exceptions.DatabaseModificationError: Cannot call save in read-only document mode (doc-mapper)

Request Data

{
	"type": "POST",
	"args": {
		"method": "education.education.api.enroll_student",
		"source_name": "EDU-APP-2025-00001",
		"args": null,
		"selected_children": "{}"
	},
	"freeze": true,
	"freeze_message": "",
	"headers": {},
	"error_handlers": {},
	"url": "/api/method/frappe.model.mapper.make_mapped_doc",
	"request_id": null
}

Response Data

{
	"exception": "frappe.exceptions.DatabaseModificationError: Cannot call save in read-only document mode (doc-mapper)",
	"exc_type": "DatabaseModificationError",
	"_exc_source": "education (app)"
}