A Kepler DR25 test signal makes corrected flux negative in quarter 7 of KIC 7448123

We compare 13 pairs of original and injected Kepler DR25 light curves for three targets selected in an earlier stress test. Twelve quarters have supported center measurements. In quarter 7 of KIC 7448123, we test 12 center samples from three artificial transits. Each has positive original corrected flux and negative injected corrected flux. All have zero quality flags in both files. The raw median added loss is 135.06% of the original corrected quarter median. After a local baseline is removed, it is 136.94%. Across four quarters of this target, corrected center loss ranges from 5.11% to 136.94%. Aperture center loss ranges from 4.51% to 5.81%. A gain calculated from original flux medians and FLFRCSAP explains most of the change. Across all 12 measurable quarters, 11 fitted gains agree with this prediction within 0.1%. The remaining gain differs by 2.21%. A separate source-value check confirms the Q7 signs and tests other windows. Related TESS work already shows corrected depths above 100%. This study adds a controlled Kepler artificial-signal comparison across quarters. It gives no planet detection, population rate, or solution to the earlier input-geometry difference. The package preserves the public source files, provenance, code, results, figures, and reproduction instructions.

Kepler DR25 · artificial transit · aperture correction · negative corrected flux · reproducible photometry · CROWDSAP · FLFRCSAP