Backlight uneven after keyboard replacement

[RioRio]

I have replaced the keyboard on a A1278. Now the keys work, but the backlight looks terrible. It is very bright in the center but its lateral areas are very dim. I am pretty sure that I have aligned it well. What else could I have done wrong?

Is there any way to fix this without buying a new backlight?

 

[2informaticos]

Probably shitty chinese keyboard.
Original backlight sheet still good?

 

[RioRio]

This is the original backlight. I did not notice it being uneven before the replacement. But I am not 100% sure, the MacBook was not powering on, I had to bridge 2 pins to start it. I wonder if maybe bending the backlight sheet could cause this?

 

[2informaticos]

Remove it and check if LEDs light correctly.
Do you note any crack on the backlight sheet?