Half burnt out LED tube lights in LED-mirror panel
Stop chasing the problem.  It is not yours to fix. It's a 100% waste of your time to try to fix it.
Simply report it again.
And this is where people go wrong.  They say &quot;But I reported it before and they DIDN'T FIX IT therefore they are totally incompetent and I should never call them again!&quot;
That completely misunderstands how troubleshooting works... especially when the troubleshooting is at someone else's premises where you can't just hang out for a day to see if that fixed it.  The simple fact is that technicians don't know.  The best anyone can do is make a best guess, try something, see what happens, amend their guess, and try again.  This is called iteration.
The &quot;best guesses&quot; are often codified on a troubleshooting flowchart from the vendor.  (or simply from experience/common sense).   Often, &quot;whether this has succeeded&quot; is not immediately evident; time must pass to expose whether the fix has held.  This is normal.
Happens all the time where people have a problem that will be uncovered on step E of the troubleshooting flowchart. However they keep firing the techs for incompetence when they've only reached step B or C.  Some people will spend thousands of dollars at this.
So report the problem again so the technician knows that the last thing didn't work.  Now, they will try the next step on the troubleshooting flowchart.