This may be an issue isolated to using LBS instead of KGS as this is what’s seen when switched to metric - LIDOS was just recently crossed and EFOB shows 1,352kgs compared to the 1,320kgs onboard a few minutes after passing.
The EWD also shouldn’t show the actual fuel onboard, the FOB and GW are coming directly from the FMS. The only place where you can find the actual fuel onboard is the ENG + FUEL SD page. In other words the EWD should match the FMS EFOB (whether that value is correct or not).
What is the fuel flow showing on the ENG + FUEL SD page?
Sorry, the flight just concluded, so unable to check - but the issue seems to only be present when using LBS so that may help point the developers in the right direction.