Ssh-agent doesn't get started on login via the desktop or via ssh

I’ve been happily using Manjaro ARM Linux on the Pinebook Pro I got some time ago, but recently ran out of room on the internal eMMC card, so I installed Tow Boot and did a fresh install of Manjaro ARM Plasma Desktop on a micro SD card with 512 GiB. It works great, except that a ssh-agent doesn’t start up when I log in, whether I do so on the console of the machine or via ssh.

Any ideas what’s going on, or how to debug it, would be greatly appreciated.