VIC Fyansford - Strange prices for Geelong region?

Hi there, I was wondering if any of the big fish or locals on here could provide me some insight into the wildly inconsistent/interesting prices in Fyansford. It seems you can get an incredibly large block 1000SQM+, very close to Geelong and other resources for WAY under what you can anywhere within 12 minutes of Geelong.

Lots in Fyansford have recently sold 400-500SQM for between 400-500k
But in the last 6 months 1100+ SQM blocks have sold for 400k
A 1400SQM is selling for 550-580k currently.

For example this block is 1200sqm, sold for $450k a few months ago.
https://www.realestate.com.au/property/12-14-zenith-cct-fyansford-vic-3218

Is this due to the Quarry that was in the area? Is it going to cost 200k+ to make some of these sloped blocks safe to build on? The 12-14 Zenith CCT Fyansford appears to be a relatively flat block so I cant imagine it would require much land work.

The highway? I've been there and while it's noisy, once you're inside with double glazed windows and decent insulation you just won't be able to hear it.

It feels too good to be true! 1200sqm for 450k and next door on a sloped block for 1400sqm 580k?!