Endpoint Monitor Status is always null when calling Traffic Manager Profile - List By Resource Group

(API version 2018-04-01)
When calling Traffic Manager Profile -> List By Resource Group in the Azure Rest API, I get back a full list of all Traffic Manager Profiles and all of their endpoints. All endpoints contain a property EndpointMonitorStatus. This property should be degraded or online, but instead it is null.

Next, I tested the Traffic Manager Endpoint -> Get method. This method returned me the correct information for EndpointMonitorStatus. So the API is able to fetch this information, but for some reason is not doing so from Traffic Manager Profile -> List By Resource Group.

Is this a bug in Azure? or am I missing something? The API documentation leads me to believe this is not desired behavior.

Start by comparing the Traffic Manager Profile - List By Resource Group response with Traffic Manager Endpoint - Get for API version 2018-04-01, focusing on EndpointMonitorStatus and the API documentation. Determine whether the profile-list response or its specification defines the null value; done means the discrepancy is corrected or documented with the expected behavior.

Written by the indexing model from the issue text.