The fonts in the sidebar view of System Settings are not rendered properly.
Uploaded a screenshot here: https://imgur.com/a/9yR8o
The icon view works fine.
I'm on Plasma 5.12.4, Frameworks 5.45.0 with Nvidia binary drivers.
Distro is KDE Neon user edition. The drivers were installed from the default repo.
I'm not 100% sure, but I think the fonts were fine before the update to KF 5.45.0.
Is this a known bug? How do I go about troubleshooting it?

This is a known regression, see https://bugs.kde.org/show_bug.cgi?id=393202

Noted. Thanks for pointing it out.
Although I don't understand what's non-standard about Noto Sans 12pt or Ubuntu 12pt, I'll just use something different in the meantime.