In reference to the issue
The first thing I did to make the filters run is use the previous istio image
istio/proxyv2:1.6.0 instead of
istio/proxyv2:1.12.0-rc.1 and it works. Why? So the envoy configuration in the repository is using v2 API which now is deprecated in the latest release. If you take a closer look at the error you can see that it is a case of misconfigured yaml. So the current configurations need to adopt v3 API as per this. Until then we need to continue using
istio/proxyv2:1.6.0 and update this issue to convert the envoy configurations to v3 API.