My source is me personally searching condo prices every day for 6 months.

Search Zillow in Cap Hill. You'll find lots of place whose prices are flat or even down over the past year.

This is the first place I clicked https://www.zillow.com/homedetails/322-Belmont-Ave-E-APT-502-Seattle-WA-98102/2078453767_zpid/

Here is aother that is down a bit https://www.zillow.com/homedetails/400-Melrose-Ave-E-APT-604-Seattle-WA-98102/49040341_zpid/

In my building prices are down 10%. https://www.zillow.com/homes/321-E-Thomas-St-Apt-301-Seattle,-WA,-98102_rb/65230412_zpid/

Some people in my HOA are really freaked about it. They are talking about changing the rental rules so people who need to move right now aren't forced to sell in a "down market".