While working on an unrelated issue, I noticed that the TagTraces method on the client will return a 400 when used. I compared the model being used (TagsServersResource, which the naming seemed odd since this method is trying to tag a Trace) has a Links property, which does not match the request format in the API docs (I can't deep link into the API docs, but the request object is TagsVulnerabilitiesRequest).
Here's an example of the behavior I'm observing: https://gist.github.com/dwalleck/5f5fc5ce0651e2a96738492218b3dd3b
When the Links property is removed from the request, the operation works as expected.