Stark Accessibility Checker

Grey overlay on my company web dashboard

The plugin works on most webpages, but for whatever reason doesn't work on our company's dashboard. We build automation systems for monitoring and controlling equipment remotely in various industries. As part of this, we develop custom online dashboards for users, which displays realtime states of hardware. As part of this, we use colours to indicate equipment running, stopped, or faulted states, including red and green. I downloaded the extension with the hopes of improving how we develop these tools, but whenever I click any of the colour-blind modes under the "Vision Simulator" tab, our dashboard goes grey (#ddd) as if an overlay has appeared over the top. I've tried Chrome and Edge browsers and the same happens in both. It doesn't happen on other websites, so I don't know whether it is related to something our web developers have done or with the Stark plugin. However, I need to figure out what is causing it, and it seems unlikely that our developers would know.

I've tried in an incognito window (logged out) and found the login box displays above the overlay (albeit off-centre for some reason), but when I log in to our dashboard, the login window disappears, and the grey overlay remains.
Our dashboard is available at: https://halo.dashboard.co.nz/