  We revisit the question of the convergence of lattice perturbation theory for
a pure SU(3) lattice gauge theory in 4 dimensions. Using a series for the
average plaquette up to order 10 in the weak coupling parameter beta^{-1}, we
show that the analysis of the extrapolated ratio and the extrapolated slope
suggests the possibility of a non-analytical power behavior of the form
(1/\beta -1/5.7(1))^{1.0(1)}, in agreement with another analysis based on the
same asumption. This would imply that the third derivative of the free energy
density diverges near beta =5.7. We show that the peak in the third derivative
of the free energy present on 4^4 lattices disappears if the size of the
lattice is increased isotropically up to a 10^4 lattice. On the other hand, on
4 x L^3 lattices, a jump in the third derivative persists when L increases. Its
location coincides with the onset of a non-zero average for the Polyakov loop.
We show that the apparent contradiction at zero temperature can be resolved by
moving the singularity in the complex 1/\beta plane. If the imaginary part of
the location of the singularity Gamma is within the range 0.001< Gamma < 0.01,
it is possible to limit the second derivative of P within an acceptable range
without affecting drastically the behavior of the perturbative coefficients. We
discuss the possibility of checking the existence of these complex
singularities by using the strong coupling expansion or calculating the zeroes
of the partition function.
