The Lebwohl-Lasher model of uniaxial liquid crystals with ( = 3, = 2) was reported earlier to undergo a crossover to a novel nematic phase at a temperature $T=T_n$. This phase has unbound topological defects in a nematic background, that pair at a lower $T_{\mathrm{\text{BKT}}}<T_n$. The transition has zero latent heat, and a specific heat and correlation length that remain finite. We discover here a significant sparseness of states or an entropy barrier `bottleneck’, between the isotropic and novel nematic phases. Passage through these sparse configurations is enabled by short-range nematic clusters dressing the defect cores. The free energy temperature derivatives determine this is a {} transition in the Ehrenfest classification. The local transformation to dressed defects induces a sharp downward decrease in the correlation length, at a precursor temperature $T_p>T_n$. Cooling through $T_p$ yields an itinerant para-nematic fluid of defects dressed with a macroscopically occupied local polar angle tilt. Correlations may de-localize these short-range nematic tilts, below $T_n$.