Junk in log filenames

I want to create log files, as in example shown:

 LogUtils.getLog2FileConfig().configLog2FileEnable(true)
                            // targetSdkVersion >= 23 需要确保有写sdcard权限
                            .configLog2FilePath(Environment.getExternalStorageDirectory().getPath() + File.separator + "LWN_logs/")
                            .configLog2FileNameFormat("%d{ddMMyyyy}.log")
                            .configLogFileEngine(new LogFileEngineFactory(context));

Problem is that filenames contains junk symbols after extention and even can not be deleted.

When i set filename as configLog2FileNameFormat("log.log") filename is as expected.

How can i fix it?

该提问来源于开源项目：pengwei1024/LogUtils