I received the following today (9/22) from Apple support in response to my query on a defect I opened re: prox sensor some weeks ago:
At this time, there isn't any new information available for this issue. I have checked with engineering and the issue is still being investigated.
So it seems clear to me that while 4.1 is better for many, it's not a complete solution for all.
FWIW, 4.2 beta 1 doesn't seem to be any different WRT sensor timing. However, I've never had any prox sensor issues with my test units so I can't say for sure if it's better or worse.
At this time, there isn't any new information available for this issue. I have checked with engineering and the issue is still being investigated.
So it seems clear to me that while 4.1 is better for many, it's not a complete solution for all.
FWIW, 4.2 beta 1 doesn't seem to be any different WRT sensor timing. However, I've never had any prox sensor issues with my test units so I can't say for sure if it's better or worse.