title: Timestamp subtraction must have the same timezones or no timezones but they are both UTC
body: <p>There are questions that addresses the same error <code>TypeError: Timestamp subtraction must have the same timezones or no timezones</code> but none faces the same issue as this one.</p>
  
  <p>I have 2 UTC Timestamps that throw that error when substracted.</p>
  
  <pre><code>print(date, type(date), date.tzinfo)
  &gt;&gt;&gt; 2020-07-17 00:00:00+00:00 &lt;class 'pandas._libs.tslibs.timestamps.Timestamp'&gt; UTC
  print(date2, type(date2), date2.tzinfo)
  &gt;&gt;&gt; 2020-04-06 00:00:00.000000001+00:00 &lt;class 'pandas._libs.tslibs.timestamps.Timestamp'&gt; UTC
  date - date2
  &gt;&gt;&gt; TypeError: Timestamp subtraction must have the same timezones or no timezones
  </code></pre>
  
  <p>Edit: I'm using <em>Python 3.6.9</em> and <em>Pandas 1.0.1</em> </p>