Which version of the SDK were you using?
In 0.8.1 the DMA support was not implemented and probably that is why the field was not initialized.
Indeed this is a problem, because uninitializing the field may trigger unpredictable behavior.
But we have recently released the 0.8.2 EAR release for the SDK, which now supports DMA, so the problem was most likely addressed.
I will investigate this issue and come back with an answer.