It’s possible to create content properties with duplicate keys via REST API

Issue Summary

When calling the /wiki/rest/api/content/{content-id}/property endpoint with the same request body, it's possible to create content properties with duplicate keys via both v1 and v2 APIs. This seems to be a race condition between the two calls, but we also saw sites on which the two properties were created a few minutes apart.

This may cause issues when trying to read and update the property, which affects apps that rely on that functionality.

Steps to Reproduce

1. Trigger two POST curl calls in the same command using the same body
2. Two properties will be created with the same key.

Expected Results

Only one property is created and the second call is rejected since a property already exists

Actual Results

The properties are created with the same key

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available