[Q] S-pen Fault

Hi all,

Ok background, ive had my phone a few years but smashed the screen! Got a full replacement front so only moved the boards and stuff across, no heating it up or anything... I found once i had turned it on and started it up I have an issue with my S-pen, when using it with just my finger its fine, however, the s pen is intermittent at best... I cannot draw in the centre of the screen at all but the outer edges are fine to a point?

Does anybody know whats going on here? Any help will be greatly received