title: Weird results for Nesbot Carbon diffInHours
body: <p>I was doing some <code>tinker</code>ing for another question here on SO. And have some weird behavior for Carbon's diffInHours. The diff of time ahead is not the same as the diff of time past. Here is my tinker commands and return values:</p>
  <pre><code>&gt;&gt;&gt; \Carbon\Carbon::now()-&gt;diffInHours(\Carbon\Carbon::now()-&gt;addHours(3))
  =&gt; 3
  &gt;&gt;&gt; \Carbon\Carbon::now()-&gt;addHours(3)-&gt;diffInHours(\Carbon\Carbon::now())
  =&gt; 2
  &gt;&gt;&gt; \Carbon\Carbon::now()-&gt;addHours(3)-&gt;diffInHours(\Carbon\Carbon::now())
  =&gt; 2
  &gt;&gt;&gt; \Carbon\Carbon::now()-&gt;addHours(3)-&gt;diffInHours(\Carbon\Carbon::now())
  =&gt; 2
  &gt;&gt;&gt; \Carbon\Carbon::now()
  =&gt; Carbon\Carbon @1595427497 {#4431
       date: 2020-07-22 14:18:17.952594 UTC (+00:00),
     }
  </code></pre>
  <p>Does anyone have any insight as to what is causing this behavior?</p>