Sony Xperia Z3: AOSP Build (Lollipop 5.0) - Time reset on device reboot

Hi,

I'm trying to build Android 5.0 for the Sony Xperia Z3 (leo) using AOSP sources and the vendor binaries provided by Sony on their Developer World website ('SW_binaries_for_Xperia_AOSP_L_MR0_v8'). System, Boot, Recovery, Cache and Userdata images are all built properly and I am able to flash them on an actual device.

However, each time the phone is restarted, the system's Date & Time settings are reset to the default, a fixed day in 1970.

From my past experience with builds for Google Nexus devices, this kind of issue is often caused by outdated or incomplete vendor files.
I attempted to build using the vendor from the software binaries available on the Sony Xperia Github project (sonyxperiadev/device-sony-leo), which is 'v7' I believe, instead of the version available in direct download, with no luck: same issue.

Has anyone encountered and/or solved this issue?
Is there a version of the software binaries I am missing, or do I need to tweak something in the source?

Any help will be appreciated.

A.Robert