svg rounding?

on this page - https://pskiinteisto.fi-s.seravo.com/     - I have an svg added as a pseudo after element but at certain screen widths (most noticeable on desktop) a line appears at the bottom. colouring the hero background red temporarily in inspector producs a red line so i think it could be a rounding up and down of the svg to either cover or reveal a sliver of background. has any one had this before and what can i try and do to fix it? position the element a pixel or so down? use clip path instead?