Single thin vertical white line after screen replacement?

I replaced a shattered iPhone 5c screen and everything seemed to go fine during installation. I was careful and transferred some parts over to the new glass/digitizer. I seated the three flex cables which I was very careful with. The first one took a little while to find the right place for it to be seated but eventually snapped in. The last 2 were very easy and snapped right into place. I replaced the metal backing for the flex cable and turned on the phone. The phone turns on and there is really nothing on the screen. Then a single thin white line appears running vertically the entire length of the screen. I am able to hold the power button then slide to power off so i know the touch screen aspect works. Has anyone seen this before? I didnt see anyone with the single thin line in the previously asked questions.