metalLB controller error: unable to process a request with an unknown content type

[Lukk17]

Version of MetalLB: 0.13.6
Version of Kubernetes: v1.25.2

installed via:
kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.13.6/config/manifests/metallb-native.yaml

with configuration as here:
https://metallb.universe.tf/configuration

apiVersion: v1
data:
secretkey:
kind: Secret
metadata:
name: memberlist
namespace: metallb-system
type: Opaque

apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
name: first-pool
namespace: metallb-system
spec:
addresses:
- 192.168.1.80-192.168.1.90
autoAssign: false
avoidBuggyIPs: true

apiVersion: metallb.io/v1beta1
kind: L2Advertisement
metadata:
name: l2advertisement
namespace: metallb-system
spec:
ipAddressPools:
- first-pool

apiVersion: metallb.io/v1beta1
kind: BGPAdvertisement
metadata:
name: bgpadvertisement
namespace: metallb-system
spec:
ipAddressPools:
- first-pool

error:

{"level":"error","ts":1665674964.7985432,"logger":"controller-runtime.webhook.webhooks","msg":"unable to process a request with an unknown content type","webhook":"/validate-metallb-io-v1beta1-addresspool","content type":"","error":"contentType=, expected application/json","stacktrace":"sigs.k8s.io/controller-runtime/pkg/webhook/admission.(*Webhook).ServeHTTP\n\t/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.13.0/pkg/webhook/admission/http.go:72\ngithub.com/prometheus/client_golang/prometheus/promhttp.InstrumentHandlerInFlight.func1\n\t/go/pkg/mod/github.com/prometheus/client_golang@v1.12.2/prometheus/promhttp/instrument_server.go:40\nnet/http.HandlerFunc.ServeHTTP\n\t/usr/local/go/src/net/http/server.go:2084\ngithub.com/prometheus/client_golang/prometheus/promhttp.InstrumentHandlerCounter.func1\n\t/go/pkg/mod/github.com/prometheus/client_golang@v1.12.2/prometheus/promhttp/instrument_server.go:117\nnet/http.HandlerFunc.ServeHTTP\n\t/usr/local/go/src/net/http/server.go:2084\ngithub.com/prometheus/client_golang/prometheus/promhttp.InstrumentHandlerDuration.func2\n\t/go/pkg/mod/github.com/prometheus/client_golang@v1.12.2/prometheus/promhttp/instrument_server.go:84\nnet/http.HandlerFunc.ServeHTTP\n\t/usr/local/go/src/net/http/server.go:2084\nnet/http.(*ServeMux).ServeHTTP\n\t/usr/local/go/src/net/http/server.go:2462\nnet/http.serverHandler.ServeHTTP\n\t/usr/local/go/src/net/http/server.go:2916\nnet/http.initALPNRequest.ServeHTTP\n\t/usr/local/go/src/net/http/server.go:3523\nnet/http.(*http2serverConn).runHandler\n\t/usr/local/go/src/net/http/h2_bundle.go:5903"}

[fedepaol]

Thanks for the report! I was just looking at this.
This is a regression caused by #1611
The webhook complains about not getting any payload, it causes no harm but it's less than optimal.
I am going to fix this, probably by reverting the change.