Not sure if this is a MPL or seaborn issue but just posting it here so that it doesn't get lost. I will investigate further later.

Running the following works as expected in python 2 and using python3 without seaborn on master (1.5.x )

import seaborn
import matplotlib.pyplot as plt


myfig, ax = plt.subplots(1,1)
ax.plot(range(100))
ax.set_xscale('log')
ax.set_yscale('log')
plt.show()

However it doesn't work with python3 see:
https://gist.github.com/jenshnielsen/5292948d67038bb77bfb