alt Hacker NewsRight. What the reporter calls a "surge in supply" is an increase in "active listings", which doesn't differentiate from listings due to new construction vs listings due to people leaving.
Also, I could not find the "active listings" data in Zumper's report[1]. And then I noticed the chart with the active listing data says it was made by Brenden Tuccinardi/KPBS, so this was done by a reporter, not a Zumper data analyst. It's a bit fishy.
[1] https://www.zumper.com/rent-research/national-rent-report
San Diego also has the strange property of being on an international border!
TJ and SD are really two parts of the same metropolis - any investigation has to see how population ebbs and flows across that border, and what the housing prices did on both sides.