Help understanding variable independence

I’m plotting a histogram of the posterior. I’m wondering why plotting “temperature” marginal varies if I comment out the “sales” sampling since temperature doesn’t depend on sales.

I’m also trying to understand why “temperature” gets capped at ~26.5 when “sales” isn’t commented out.

I’ve tried isolating sampling of temperature within a pyro.plate as well as sales but I don’t see any changes while plotting the posterior.

import pyro
import pyro.distributions as dist
from pyro.infer import EmpiricalMarginal
from pyro.infer.mcmc import MCMC
from pyro.infer.mcmc.nuts import HMC
import matplotlib.pyplot as plt


def model():
    cloudy = pyro.sample("cloudy", dist.Bernoulli(0.3), infer={"enumerate": "sequential"})
    is_cloudy = cloudy == 1.0
    temp_mu = 13.0 if is_cloudy else 24.0
    temp_si = 5.0 if is_cloudy else 7.0
    temperature = pyro.sample("temperature", dist.Normal(temp_mu, temp_si))
    sales_mu = 200.0 if (not is_cloudy and temperature > 26.5) else 50.0

    # HELP: commenting the line below seems to affect "temperature" sampling
    sales = pyro.sample('sales', dist.Normal(sales_mu, 10.0))

def build_posterior():
    hmc_kernel = HMC(model=model, step_size=0.09, num_steps=4)
    posterior = MCMC(kernel=hmc_kernel, num_samples=500, warmup_steps=50)
    return posterior

posterior = build_posterior()
marginal = EmpiricalMarginal(posterior, "temperature")

plt.hist([marginal().detach() for x in range(5000)], 50)