  Potential contribution from gamma-ray sources to the Galactic diffuse gamma
rays observed above 100 TeV (sub-PeV energy range) by the Tibet AS{\gamma}
experiment is an important key to interpreting recent multi-messenger
observations. This paper reveals a surprising fact: none of the 23 Tibet
AS{\gamma} diffuse gamma-ray events above 398TeV within the Galactic
latitudinal range of |b| < 10 deg. come from the 43 sub-PeV gamma-ray sources
reported in the 1LHAASO catalog, which proves that these sources are not the
origins of the Tibet AS{\gamma} diffuse gamma-ray events. No positional overlap
between the Tibet AS{\gamma} diffuse gamma-ray events and the sub-PeV LHAASO
sources currently supports the diffusive nature of the Tibet AS{\gamma} diffuse
gamma-ray events, although their potential origin in the gamma-ray sources yet
unresolved in the sub-PeV energy range cannot be ruled out.
