negative.
the problem first surfaced for me around march. And it has happened about four times since then, with no apparent pattern between the intervals. In three of the four cases it was fixed by rebooting the phone, in one case the phone apparently fixed itself after half an hour of darkness.

I do have unstavle apps installed but cant think of any that would cause this; and the problem is impossible to reproduce so its very difficult to file a useful bug report.

Have you installed any unstable apps recently that could cause this? What was your uptime when it happened, I think it may be related to long uptime.