Having never seen the XK0-004 material, I'm not sure what the comparison would look like. However, I just went though the first few pages of the Applied Lab for lesson 6 and didn't have any issues with it. The symbolic link seemed to work and grade fine as well. I also believe that the intention of the Applied labs is not to provide the full instructions on exactly what to type (which is different than the Assisted labs), but I personally think it is giving an appropriate amount of hints to be successfully completed. Having gone through all of the CM Learn and Labs product for Linux+ late last year I don't recall issues with the grading or content, but, yes, I have found some overall production lab errors in the past, but I don't recall any specifically for Linux+. I do agree with Samuel that asking for CompTIA assistance could be helpful. In the labs, under the Help tab, there are links to Report a Bug and Submit a Report Request. Those might be a good place to start.