Curious RSA Display Output

[NemesisUK]

Recently the road into home has had a change of speed limit from the original 60mph to 40mph  then 30mph to directly from 60mph to 30mph. All the signage and road markings have been changed to reflect to the new limit (apparently for a provisional period to assess compliance).

The RSA always reflected the correct limit change and I assumed the camera was interpreting the signage but now the RSA shows the new 30mph only fleetingly before reverting to the old 40mph and then showing the 30mph limit change at the old location, where there now is no indication on the road or signage of the change.

It appears the camera correctly identifies the signage but then the (outdated) navigation information overrides and forces the old info to be displayed.

I know this is only a 'driver aid' and shouldn't be relied on but in an unfamiliar location it could so easily result in unintentional speeding.

I wonder if there is a way of prioritising the camera info over the navigation data?