Create 2021.3.5 on Linux - cache not connecting and shadercache issues

OS: Arch Linux
GPU: 3090 RTX driver 470.63.01

Create 2021.3.5 starts normally, Cache is ON, as indicated in the UI.
As soon as I click “localhost”, I get:

2021-09-18 07:49:50  [Warning] [omni.ext-live.plugin] Omniverse Cache is disabled! It can be turned on in Omniverse System Monitor.

And the the Cache is OFF.
I can browse the files fine on the Nucleus page of the Launcher. Also cache settings indicate everything is fine, Cache - Access logs show no errors.

Additionally, I get the following errors related to shadercache:

2021-09-18 07:46:58  [Error] [carb] Failed to create file '${ov_root}/cache/Kit/102.1/2027b54e/shadercache/release/96c85d244339ec0c5fed6dce1c9d796b.v' for writing (File exists)

I nuked these files (they are obviously writeable), restarted Cache, it regenerated shader cache only to have the same errors on subsequent start.