NPE when using MP Config with RESTEasy Client on the class path

java.lang.NullPointerException: null
at org.jboss.resteasy.microprofile.config.BaseServletConfigSource.getPropertyNames(BaseServletConfigSource.java:51) ~[resteasy-jaxrs-3.15.0.Final-redhat]
at io.smallrye.config.ConfigValueConfigSourceWrapper.getPropertyNames(ConfigValueConfigSourceWrapper.java:53) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigSources.iterateNames(SmallRyeConfigSources.java:41) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigSourceInterceptorContext.iterateNames(SmallRyeConfigSourceInterceptorContext.java:25) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.ConfigSourceInterceptor.iterateNames(ConfigSourceInterceptor.java:58) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigSourceInterceptorContext.iterateNames(SmallRyeConfigSourceInterceptorContext.java:25) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.AbstractMappingConfigSourceInterceptor.iterateNames(AbstractMappingConfigSourceInterceptor.java:26) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigSourceInterceptorContext.iterateNames(SmallRyeConfigSourceInterceptorContext.java:25) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.ProfileConfigSourceInterceptor.iterateNames(ProfileConfigSourceInterceptor.java:74) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigSourceInterceptorContext.iterateNames(SmallRyeConfigSourceInterceptorContext.java:25) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.ConfigSourceInterceptor.iterateNames(ConfigSourceInterceptor.java:58) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigSourceInterceptorContext.iterateNames(SmallRyeConfigSourceInterceptorContext.java:25) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.PropertyNamesConfigSourceInterceptor.iterateNames(PropertyNamesConfigSourceInterceptor.java:23) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigSourceInterceptorContext.iterateNames(SmallRyeConfigSourceInterceptorContext.java:25) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfig$ConfigSources.generateDottedProperties(SmallRyeConfig.java:704) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfig$ConfigSources.<init>(SmallRyeConfig.java:559) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfig.<init>(SmallRyeConfig.java:68) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigBuilder.build(SmallRyeConfigBuilder.java:449) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigFactory$Default.getConfigFor(SmallRyeConfigFactory.java:59) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigProviderResolver.getConfig(SmallRyeConfigProviderResolver.java:76) ~[smallrye-config-core-2.10.0.jar:?]
at io.smallrye.config.SmallRyeConfigProviderResolver.getConfig(SmallRyeConfigProviderResolver.java:64) ~[smallrye-config-core-2.10.0.jar:?]
at org.eclipse.microprofile.config.ConfigProvider.getConfig(ConfigProvider.java:85) ~[microprofile-config-api-2.0.0.jar:?]
...