Blank <settings>/<system> screen?

I have a fully up to date HA running in Hyper-V on a windows host.
I recently started getting nothing but a blank screen when I navigate to / in the GUI. Is this a known issue, and any idea how I resolve it? I have tried a platform restart, but obviously can’t even get to many of the system settings in the GUI!

Home Assistant 2022.9.5
Supervisor 2022.09.1
Operating System 9.0
Frontend 20220907.1 - latest

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