My theory is the same as yours, but shouldn't removing platform and readding fix this already?
I even went to the ionic.io.bundle.min.js to make sure it was the correct app_id added, and it was.
Also, maybe it's not connected, but I feel like my bower.json is out of date, I can see in it some old versions for my plugins and even some plugin that I already deleted. Maybe it's calling the wrong ionic-service-core & deploy? How can I update its content?
I will make sure it's fetching from the same app_id with the proxy you mentionned...