In Ventura, with each reboot new private and public keys get created

Since updating to macOS Ventura, every time I restart my computer, new private and public keys identified only by the name <key> get created in my login keychain. (Each pair is in addition to the previous pair, so they rapidly accumulate.) I can delete them without any obvious impact.

Any ideas? Is anyone else experiencing this?

(I think I remember a similar problem a few OS's back that didn't get fixed until the next major macOS update.)