LCD display connection problem?

So after replacing the charging port on my M9 the screen started acting up. It worked at first then only the backlight worked. After reconnecting the lcd cable a couple times its working now but any downward pressure on the screen causes it to flicker, fade, spazz out colors and eventually turn black, it goes back to normal if you remove the pressure

Is the an explanation for this? I was told by a local repair shop that the lcd cable was fine as most problems are either the screen works or it doesn't.

Should I just leave it like this? I can't use a case as the added pressure of a case induces the issue, but without a case its like new. Very annoying.