When useMDCLogging is set to true on a CamelContext with camel-zipkin, the application fails to start. The error message is java.lang.NoClassDefFoundError: brave/internal/propagation/CorrelationFieldScopeDecorator.
The reason might be that the brave.context.slf4j.MDCScopeDecorator from brave-context-slf4j, introduced into ZipkinTracer with
CAMEL-12721, extends brave.internal.propagation.CorrelationFieldScopeDecorator, which seems not to get exported by the brave bundle https://github.com/openzipkin/brave/tree/5.6.5/brave, according to its bnd file (https://github.com/openzipkin/brave/blob/5.6.5/brave/bnd.bnd). Possibly this is why the instance creation fails.
The solution could be to use only exported brave classes (effectively recreating MDCScopeDecorator) or maybe let OSGi create the MDCScopeDecorator instance.