Why won't my Data/GPS work during phone calls?

[pengfoong]

No Data/GPS during phone call.

I noticed that after the update to the latest developer preview, whenever I'm on a phone call, data and GPS will not work. It used to work last time, at least for the data.

Anyone else having the same problem?

I have a Lumia 820

 

[hotphil]

Might not be related to the DP.
As I understand it, the tech that some networks have named "4G" means that voice and data can't both be used at the same time. Not sure about the GPS though.