You can workaround this issue by switching to Chrome v. 49, which is currently the beta release @ Chrome Release Channels - The Chromium Projects. This probably doesn't help anyone with an actual user base.
Maybe this is a sign that the test coverage for synchronous XMLHTTPRequests is not at par with async requests. It's probably time for UI5 to go fully async. Actually, it was a good time to go async when the project started, but now is also good.