Frontend & browser·Performance and Core Web Vitals
you went to click the button, an ad loaded above it, and you clicked something else entirely.
Cumulative layout shift
Also calledCLS, layout shift
A score accumulating every unexpected movement of visible content, weighted by how much moved and how far. The usual causes are images without dimensions, webfonts swapping, and content injected above existing content. Shifts within 500 milliseconds of a user interaction are excluded, which is why opening an accordion does not count and an ad slot filling in does.