There's a lot of drama in that Issue, and then, at the very end:
Thanks for sharing your concerns here. We have been progressing use of our SDK in more use cases for our clients. However, our goal is to make sure that the SDK is used in a way that maintains GPL compatibility.
the SDK and the client are two separate programs
code for each program is in separate repositories
the fact that the two programs communicate using standard protocols does not mean they are one program for purposes of GPLv3
Being able to build the app as you are trying to do here is an issue we plan to resolve and is merely a bug.