What is causing the issue of the charging not working properly?

Now, I have somewhat isolated the issue and have a solution. The part I don't understand is, what part of the front display frame specifically is causing this weird ground issue?

One solution was to lift up the screen and just put it back on.

The other solution was to change the screen.

I just had to lift up the screen and put it back on (Only need to lift up the bottom part) for my mums phone like literally an hour ago and it fixed the charging issue where the battery % would not go up and it kept saying 'This lightning cable is not a certified blah blah' which disappeared when I did the solution.

A few other users on iFixit have had this issue with the iPhone 6 and 6 Plus specifically.

Bonus question: How does one get moderator?