Mortgage rates have been coming down, but there has yet to be a spike in homebuying activity—and one leading indicator has even declined. Pending home sales, or signed contracts leading up to a sale, fell for the first time in nearly three months, slipping about 1% during the four weeks ending Sept. 21 compared to a year earlier, according to a Redfin report on Thursday. That’s despite the weekly average mortgage rate sliding for nine consecutive weeks, hitting an 11-month low of 6.26% after reaching 6.8 ...