  In a previous paper we reported on a discontinuity in the extreme horizontal
branch (EHB) of the Galactic globular cluster NGC6752, which we called the
second U-jump. This feature was attributed to a combination of post zero-age
horizontal branch evolution and diffusion effects. In this follow-up study we
analyze other EHB clusters and show that the second U-jump is a common feature
among EHB clusters reaching T_{eff}\ge 23,000K, and that its onset in different
clusters converges around T_{eff}\sim 21,000\pm3,000K. We also present
near-ultraviolet diagrams of \omega Cen and NGC2808, the only two objects with
spectroscopically confirmed ``blue hook'' stars (T_{eff}\ge 35,000K). We
confirm predictions of a photometric discontinuity separating late from
early-helium flashers. Moreover, we present empirical evidence that the second
U-jump population might be mainly composed by early-helium flashers. Lastly, we
revisit the discussion on the ubiquitous nature of the gaps and jumps so far
identified in the blue HB tails, suggesting a possible discrete nature of the
distribution in temperature of the HB stars.
