My weird hobby had me stubble on some random phenomenon

For context, sometimes I go on maps, find a cool house and pull up the Zillow or Redfin and understand the financials of the property. Idk it’s a fun way to pass the time during break.

Anyways, I live in the Bay Area and ruby hills is a more affluent area. A community of McMansions going exclusively north of 3 million. In the mid-90s, people who bought these houses for goats and pumpkin sold their homes for north of 2 million dollars within a decade of ownership. The second owners then all sold for a loss of atleast half a million. Some of these cases are before the ‘08 crash.

My questions are what could have caused a pull for a million and a half in property value is only 10 years and what could have caused the immediate crash of value? I can’t attach screenshots but I pasted out a good example.

1/21/2005
Sold
$1,229,000
-56.1%
$148/sqft
Source: Public Record Report
7/30/2002
Sold
$2,800,000
+413.8%
$337/sqft
Source: nan CCAR #11150059 Report
9/23/1999
Sold
$545,000
+51.4%
$66/sqft
Source: Public Record Report
7/20/1998
Sold
$360,000
$43/sqft