LED backlight hotspot
Your problem is you are using &quot;single rank&quot; LED's , these have brightness that can vary +/- 50% from part to part, it's even worse at lower drive currents.
You need to select a part that has &quot;intensity binning&quot; and either order a specicic intensity bin, or get a part where each reel is all of the same bin.
If you are making white backlights, you also need color bins.
I helped a colleague scrape off about 10,000 LEDs from backlight PCB's, because they were un-binned, we sprayed some flux on, heated up the PCB with a blow torch, and wiped em off with a cotton rag. A mistake you only make once!
Here is an extract from a random LED datasheet showing the binning codes and typical variation.