Game now going black consistently

Basically large sections of the screen goes black in rectangular chunks. Character models are still visible but that's about it. I'm seeing this in multiple zones and shortly after starting.

I've had the iPad version since release, this issue started only yesterday but its now happening all the time. Bit of a worry given that there have been no game updates or iOS updates to explain the change.

It would be nice to know if this issue was in the patch we are waiting on. I'm pretty close to calling this unplayable.