Several users have complained of a 'stage light' anomaly in their MacBook Pro displays. iFixit wrote in a blog post that it has identified the cause of the issue and attributes it to the manner in which the display cables connect to the display controller beneath the Touch Bar. This design causes the cables to tear overtime giving the uneven backlighting effect when the display is opened beyond a certain angle. More worrisome, however, is the fact that getting it repaired can prove to be a costly affair.
https://www.notebookcheck.net/iFixit-Apple-MacBook-Pro-stage-light-issue-turns-a-6-problem-into-a-600-disaster.397341.0.html