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The dark photon is a well motivated candidate for the dark matter that comprises most of the mass of our visible Universe, leading to worldwide experimental and observational efforts toward its discovery. A primary tool in this search is the cavity haloscope, which facilitates resonantly enhanced conversion to photons from both dark photons and axions. In this context, limits from axion search experiments are often directly converted into dark photon constraints, without re-analyzing the original data. However, this rescaling may not fully capture all of the relevant physics due to various reasons. By reexamining data taken by the Taiwan Axion Search Experiment with Haloscope experiment, we derive a world-leading constraint on the dark photon parameter space, excluding <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mo stretchy="false">|</a:mo> <a:mi>ε</a:mi> <a:mo stretchy="false">|</a:mo> <a:mo>≳</a:mo> <a:mn>2</a:mn> <a:mo>×</a:mo> <a:msup> <a:mn>10</a:mn> <a:mrow> <a:mo>−</a:mo> <a:mn>14</a:mn> </a:mrow> </a:msup> </a:math> in the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mrow> <e:mn>19.46</e:mn> <e:mi>–</e:mi> <e:mn>19.84</e:mn> <e:mtext> </e:mtext> <e:mtext> </e:mtext> <e:mi mathvariant="normal">μ</e:mi> <e:mi>eV</e:mi> </e:mrow> </e:math> mass range, which exceeds the naïve “rescaling limit” by roughly a factor of two. We emphasize that accounting for the scanning timing information is crucial for deriving limits for the polarized dark photon case. In the data, we also analyze a tentative signal excess with a local significance of <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"> <h:mrow> <h:mn>4.7</h:mn> <h:mi>σ</h:mi> </h:mrow> </h:math> ( <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"> <j:msub> <j:mi>m</j:mi> <j:mi>X</j:mi> </j:msub> <j:mo>≃</j:mo> <j:mn>19.5</j:mn> <j:mtext> </j:mtext> <j:mtext> </j:mtext> <j:mi mathvariant="normal">μ</j:mi> <j:mi>eV</j:mi> </j:math> ) that persists in the absence of a magnetic field. While this excess mimics the behavior of a dark photon signal, it has been excluded by recent results from the HAYSTAC and ORGAN-Q experiments. This case study, nevertheless, highlights the risk of discarding valid dark photon signals when relying on axion-specific magnetic field vetoes.