It sounds weird, but GBP rankings often “randomly” expand because of how local search signals fluctuate. On Google, a Google Business Profile doesn’t rank in a fixed radius visibility shifts based on proximity, relevance, and prominence. Sometimes a profile gains new citations, fresh reviews, behavioral signals (clicks, calls, direction requests), or category relevance without you actively changing anything. When those signals cross a certain threshold, the map pack radius can suddenly widen.
Another factor is competitor movement. If nearby businesses lose reviews, get suspended, change categories, or become less active, your listing can expand simply because relative authority improved. Core updates and local algorithm tweaks also reweight signals, which can create that “random expansion” effect.
So it’s not truly random it’s usually accumulated trust signals + competitor shifts + algorithm recalibration hitting a tipping point.