⚡ Quick Fix (TL;DR)

The Culprit: Applying the full-bleed 100vw technique separately to individual sections (rather than once, to a single top-level wrapper) leaves other sections centering relative to their own inconsistent container instead of the true viewport, producing a small, hard-to-trace horizontal offset.

The Fix: Wrap the page's entire content in one single element and apply the full-bleed technique there, once. Let everything else inside center normally relative to that one correctly-anchored wrapper, rather than each section doing its own separate breakout.

.page-wrap {
  width: 100vw;
  position: relative;
  left: 50%;
  right: 50%;
  margin-left: -50vw;
  margin-right: -50vw;
}