Actually the first start after deleting ~/.cache/mesa_shader_cache works without corruption, but when I restart steamvr home a couple of times, often random textures are corrupted. Here is another example:

Should be fixed with https://cgit.freedesktop.org/mesa/mesa/commit/?id=ae77f1236862e73c1ac250898924c648d481bda4
Thanks for reporting this!
Indeed fixed upstream
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
I have seen this on my Vega 64 twice with two different user accounts.

On the very first start of SteamVR (at least the first time in a while) there is visual corruption visible in SteamVR Home.
On subsequent startups of SteamVR Home, this corruption is completely gone and everything looks perfect.
It looks like this corruption even casts a shadow!