Schematic of how optical flares drive systematic Gaia position shifts. At peak brightness (green), the centroid is pulled upstream toward the compact flare; as it fades (red), the centroid drifts back downstream toward the extended jet emission. Gaia cannot resolve these structures—its PSF is far larger than the jet scale (bottom)—but submilliarcsecond centroid precision captures the shift. An interactive version of this figure is available at A. V. Plavin (2025).