We characterize the radius-dependent observed transiting eccentricity distribution of 219 warm (P = 8─50 days) systems with only one transiting planetary candidate identified during Sectors 1─69 of the Transiting Exoplanet Survey Satellite (TESS) mission. Using the "photoeccentric effect" in a hierarchical Bayesian framework, we first model the population using discrete planetary size bins (sub-Neptunes, sub-Saturns, and Jovians). We then develop a continuous mixture model with weights governed by a logistic sigmoid function of radius. We find that the warm-single population is best described by two components: a dominant low-eccentricity mode (<elow> = 0.039−0.038+0.018 ) and a secondary dynamically excited mode (<ehigh> = 0.466−0.068+0.067 ). The fraction of planets belonging to this high-eccentricity component increases strongly with planet radius, characterized by a transition at a break radius of Rbr = 9.2−1.1+1.9 R⊕. This trend places warm sub-Saturns predominantly on the same low-eccentricity track as sub-Neptunes. In contrast, warm Jovians (8─16 R⊕) are frequently eccentric, with 65−12+13% of the population in the high-eccentricity mode. Under the assumption of a two-component model, we see tentative evidence for a bimodal Jovian distribution at ∼2.7σ. Finally, we identify a nonnegligible tail of highly eccentric sub-Neptunes (1─4 R⊕), which comprise 16.2−6.4+5.2% of the population, consistent with excitation by nontransiting external companions.