GPS not as accurate after power button fix

A couple days ago I opened my iphone to replace the proximity sensor cable to fix my stuck power button. As it turns out I need to go back in to fix the proximity sensor part now.

But I also noticed the GPS in maps whilst it still works, seems to get stuck in spots.. then will catch up, it often has the blue circle around it meaning it is less accurate (using cell towers) or it goes grey, then for a few seconds has the pulsating blue ball again..

So basically.. what did I screw up in there?