It's real. It started in June. Inventory has risen every month since June and sales have stayed the same or declined. Seattle was insane before June though. Homes were receiving multiple offers within days of being listed and going between 10% and 30% over asking price with sellers throwing in all sorts of crazy contingencies (no inspections allowed, rent from buyer for 2-3 months at some ridiculously low rate, etc.)
As one anecdote, my neighbor had arguably one of the nicest homes in one of the more sought after neighborhoods in Seattle. They sold their home in September after it "sat" on the market for 12 days and sold exactly for ask. The price was 16% less than they were estimated at in July, which is what probably triggered them to sell I guess.
Depending on which real estate agent you ask, Seattle was absolutely insane before and now it's getting back to slightly above normal levels and will stay there for a while. Others will say if this continues for a few months it's a sure sign of the bubble popping. Inventory will probably go down a little bit in the next few months mostly due to eager profiters taking a break during the usually slow winter months. Buyers will probably decrease a little bit too due to interest rate hikes. Next spring will be the real test.
Condos and rental prices don't seem affected yet, but those tend to lag homes in my experience. Seattle does have horrible density so maybe condos will stay strong at their ridiculous $550k median price.