Simcity3000 (unlimited) - Land value revenue bug.

Although I realize that simcity 3000 is way past it's days, but
has anyone come across the following scenario in simcity 3000 Unlimited?

City 2,150,000 million inhabitants
All zones high density with majority of land values in commercial and
residential zones being stated as "Astronomical".
At some point, the scrolling news bar shouts "Land values low..." and the
budget which was 200,000 in surplus is now reading -500,000 in the red
although if you query the individual buildings they are still saying land
value: astronomical.

I've looked around for game patches, but there doesn't seem to be any at
all. Has anyone come accross this bug before (including finding out what
the triggering factors are) and is there a way to work around it or even
kill this bug entirely?