The way the low and high functions are calculated, https://github.com/pysal/pointpats/blob/master/pointpats/distance_statistics.py#L627, it appears to be confusing since it depends on the pct parameter whereas it shouldn't. If pct=1 then the low and high envelopes are the same as can be seen below.

realizations = PoissonPointProcess( spp.window, spp.n, 10, asPP = True)
kenv = Kenv( spp, intervals = 20, realizations = realizations, pct = 1)
kenv.plot()

If pct = 0.05 having the same realizations, then,

If there is an intention to incorporate some sort of p - value in the graphs, then from what I know this p - value is determined exclusively by the amount realizations and nothing else. Finally, I would suggest to have an assertion about pct valid values.

Thanks,

Vasilis