Touch is 'off' after LCD replacement

Hello,

I replaced the screen of a Nexus5 which was broken. Before replacement, touch was working great (although glass was broken).

What happens is that it seems to be registering the touch, although placing them in the wrong area. Generally speaking, i need to touch 1 inch above where i want to. This seems to change a bit between reboots though.

Could this be an installation-failure? Bad screen? Bad connector somewhere? Could cleaning the phone with the proper stuff help fix this?

Thank you in advance