Lattice computations of the high-temperature topological susceptibility of
QCD receive lattice-spacing corrections and suffer from systematics arising
from the type and depth of gradient flow. We study the lattice spacing
corrections to χtop semi-analytically by exploring the behavior
of discretized Harrington-Shepard calorons under the action of different forms
of gradient flow. From our study we conclude that Nτ=6 is definitely
too small of a time extent to study the theory at temperatures of order
4Tc and we explore how the amount of gradient flow influences the
continuum extrapolation.Comment: 10 pages, 8 figures (published version