A new arXiv preprint (Zapatero Osorio et al., 2026) presents the first quantitative estimate of magnetic star-planet interaction for a terrestrial exoplanet, using high-resolution optical spectra to detect flares phase-locked to Proxima d's orbit and intensity modulations tied to Proxima b. Methodology relied on time-series analysis of Fe I lines for rotation (84.9 d) and flaring duty cycle (4.8%), plus prewhitening of chromospheric indicators (H-alpha, Na I, Ca II) revealing orbital and synodic peaks; no sample size or total observing baseline is stated, limiting statistical power. This is a preprint, not yet peer-reviewed. Modeling via helicity-driven reconnection yields a plausible -16 G polar field on Mars-sized Proxima d (range 3-280 G), but assumes unmeasured stellar dipole geometry and planetary radius—key uncertainties that could alter atmospheric erosion rates by orders of magnitude. Earlier work (Anglada-Escudé et al., Nature 2016) established Proxima b's Earth-like orbit without magnetic context; combining both shows the system may host competing processes where flares drive both atmospheric loss and transient auroral heating, a dynamic missed in habitability assessments focused solely on insolation. The preprint's synodic-period signal implies prograde orbits, yet lacks multi-wavelength confirmation that could distinguish reconnection from coincidental stellar variability.