### Environment

* Dubbo version: 2.7.5
* Operating System version: win10 or centos7
* Java version: 1.8.0
* Zookeeper version: 3.5.6

### Steps to reproduce this issue
My previous dubbo service version was 2.7.3. Today, I upgraded to 2.7.5. I found that the metadata can't be displayed all the time. The dubbo service registry in zookeeper, but zookeeper not /dubbo/metadata node path view.  If I switch back to 2.7.3 and 2.7.4.1, it can be displayed. Are there any bugs? I need help~~

xml-config:
`<dubbo:metadata-report address="zookeeper://192.168.11.100:2181?backup=192.168.11.105:2181" />`
```

@SuppressWarnings({"unchecked"})
    public void setRegistries(List<? extends RegistryConfig> registries) {
        this.registries = (List<RegistryConfig>) registries;
    }
    @Parameter(excluded = true)
    public String getRegistryIds() {
        return registryIds;
    }
    public void setRegistryIds(String registryIds) {
        this.registryIds = registryIds;
    }
    public MonitorConfig getMonitor() {
        return monitor;
    }
    public void setMonitor(String monitor) {
        this.monitor = new MonitorConfig(monitor);
    }
    public void setMonitor(MonitorConfig monitor) {
        this.monitor = monitor;
    }
    public String getCompiler() {
        return compiler;
    }
    public void setCompiler(String compiler) {
        this.compiler = compiler;
        AdaptiveCompiler.setDefaultCompiler(compiler);
    }
    public String getLogger() {
        return logger;
    }