title: RuntimeError: stride is not equal to 1 in unit tests
body: <p>I am building an app using vaex v4.9.1 and python 3.9. I use limits function to get the min and max combos for two axes like so:</p>
  <pre><code>    limits = df.limits(list(axes_val.values()), delay=False, selection=True)
  </code></pre>
  <p>Just recently randomly all of my unit tests broke, and they all brake on the  line above. The error that is produced is <code>RuntimeError: stride is not equal to 1</code>. I tried to track down where this error is originating from but haven't been able to find it. If I run the application normally it works.</p>
  <p>How do I fix these unit tests? Where does this stride error come from?</p>
  <pre><code>Software information
  
  Vaex version vaex==4.9.1
  Vaex was installed via: pip
  OS: Windows 10
  </code></pre>