Describe the bug
When first time sending below identity headers:

Compass-User-UUID: 12345
Compass-User-Email: john.doe@example.com

No issue occurs, but when we are changing the ID but keeping the same email like below:

Compass-User-UUID: 0268fbb2-ee3c-479a-88bb-d4d47e5725aa
Compass-User-Email: john.doe@example.com

To Reproduce
Steps to reproduce the behavior:

1. Create a request with Compass-User-UUID and Compass-User-Email headers
2. Create another request but change only the value of Compass-User-UUID
3. Got 500 error

Expected behavior
it should return more informative and concise error e.g. (409 - User email already existed with different ID)