React is the new PHP: a dangerously welcoming ecosystem for amateurs. If you look at the trace, you see it's firing a timer for LazyImage every 300 milliseconds that that's causing constant repaints. It's terrible, but no one believes in craftsmanship anymore. :-)

            // Give react a chance to render before starting to poll
            // This gives us more chance of the opacity transition being visible
            // Should also fix rendering glitches in firefox where native image placeholder shows briefly
            setTimeout(pollForComplete, 300);
        },

Hmm, settimeout is one shot, setinterval is the repeating one, unless that’s calling itself recursively?

Anyway using delays hoping that things are in place in 300ms is asking for trouble, I thought reacts whole thing was to put everything in a component lifecycle callback so everything happens in the order it needs to

Good point! There must be some other interval causing the timer to be set.

Hello! Thanks for having a fossick through our code ;) Happy to report that the issue has now been resolved. I've added a post explaining the underlying cause a little up in the thread. (I'm not sure how notifications work on HN, so figured I'd drop a reply here, too).

Awesome!

Doesn't seem to happen on the font information page:

https://klim.co.nz/retail-fonts/signifier/