  We study infrared QCD effects in radiative quarkonia decays. We examine the
endpoint region z -> 1 of the photon spectrum. We point out a cancellation
mechanism for the corrections in $\alpha_s^n \ln^{m} (1-z)$, $m \leq 2 n$, in
the short-distance coefficient for the color-singlet Fock state in the
quarkonium. The cancellation is due to the coherence of the color radiation,
and applies even though logarithmic contributions are present in the jet
distributions associated with the decay. We comment on the implications of our
results for the modeling of hadronization in the endpoint region and for the
role of color-octet states in the quarkonium.
