Hi @thewonglv - my client decided he didn’t want any interactions anyway so its a bit hard to put them back in now as bug was only happening on live site and I can’t publish the site with those effects active.
To try and replicate - I had the logo and text and button fade in on page load all separately.
and a footer and header set to fixed.
Then on live the headers didn’t fix properly and shook on scroll until stopped scrolling when they would jerk back into proper position.
Once removing all page load fade in effects the issue stopped and the fixed sections worked as expected.