Yes, it's
a brand new issue related to this REAGL mode thing. It's supposed to be better in some way, when it works.
Sorry, I wasn't aware of it yet yesterday because it was introduced only two days ago; my custom combination of code didn't show it. There are also still some lingering issues with landscape mode as a result of this particular change. Such are the joys of nightlies. :P
Edit: hah, jinx.