Similar issue like: https://issues.jboss.org/browse/ENTESB-9525.

Reproducer you can find attached. It writes, that PATCH method is not allowed, but in fuse doc: https://access.redhat.com/documentation/en-us/red_hat_fuse/7.0/html/apache_camel_component_reference/restlet-component, you can find that PATCH method should be supported.

Also in source code you can see there are only methods PUT and POST: https://github.com/apache/camel/blob/c69affc49415b190645ce25536ffd62348c4fe34/components/camel-restlet/src/main/java/org/apache/camel/component/restlet/DefaultRestletBinding.java#L290