title: LaTeX labels in matplotlib not consistent
body: <p>I try to use LaTeX labels in matplotlib plots, but they get compiled inconsistently. In the screenshot below you see, that not only the axes' labels, but also not all x- and y-ticks are rendered in LaTeX. </p>
  
  <p><a href="https://i.stack.imgur.com/k1hpC.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/k1hpC.png" alt="Python plot with latex labels"></a></p>
  
  <p>The MWE for the plot above is given by</p>
  
  <pre><code>#!/usr/bin/python3
  
  import matplotlib.pyplot as plt
  
  fig = plt.figure()
  axes = fig.add_axes([0.1, 0.1, 0.8, 0.8])
  
  # FONT
  plt.rc('text', usetex=True)
  plt.rc('font', family='serif')
  
  plt.xlabel(r'$y$', fontsize=18)
  plt.ylabel(r'$x$',fontsize=18)
  
  # PLOT
  axes.plot([1,2,3], [1,4,9], label=r'$x^2$')
  
  # LEGEND
  axes.legend(numpoints=1, loc=1, prop={'size':15})
  
  plt.show()
  </code></pre>
  
  <p>I tried this on a Debian system and macOS both with TeX Live 2018 installed.</p>
  
  <p>How do I get all labels consistently rendered by LaTeX?</p>
  
  <p>(Note: In the end I want to use Fourier as the math font and ebgaramond as the text font)</p>