title: Ionic Error v.context.$implicit is undefined
body: <p>I have the error in my code. 
  The error says like this:
  v.context.$implicit is undefined</p>
  
  <p>The problem is, sometimes it error, and sometimes it doesn’t…
  Can somebody explain why it happen…</p>
  
  <p>This my html code:</p>
  
  <pre><code>&lt;ng-container *ngFor="let time of item.timeInfo | keys" &gt;
      &lt;ion-row *ngIf="time == thisDay"&gt; 
        &lt;ion-col col-3 no-padding&gt;
          &lt;ng-container *ngIf="checkTime(); else closeButton"&gt;
            &lt;button small ion-button block color="secondary" outline&gt; OPEN &lt;/button&gt;
          &lt;/ng-container&gt;
          &lt;ng-template #closeButton&gt;
            &lt;button small ion-button block color="danger" outline&gt;Close &lt;/button&gt;
          &lt;/ng-template&gt;
        &lt;/ion-col&gt;
        &lt;ion-col col-9 &gt;
          {{ item.timeInfo[thisDay].open }} - {{ item.timeInfo[thisDay].close }}
        &lt;/ion-col&gt;
      &lt;/ion-row&gt;
    &lt;/ng-container&gt;
  </code></pre>
  
  <p>Here my json code:</p>
  
  <pre><code>"item":{
     "timeInfo": {
              "Sat": {
                  "open": "11:00",
                  "close": "21:00"
              },
              "Sun": {
                  "open": "9:00",
                  "close": "21:30"
              },
              "Mon": {
                  "open": "11:00",
                  "close": "22:30"
              },
              "Tue": {
                  "open": "12:00",
                  "close": "22:00"
              },
              "Web": {
                  "open": "12:00",
                  "close": "22:30"
              },
              "Thu": {
                  "open": "9:30",
                  "close": "22:30"
              },
              "Fri": {
                  "open": "12:30",
                  "close": "22:00"
              }
          },
   };
  </code></pre>
  
  <p>And here my version:</p>
  
  <pre><code>@ionic/cli-utils  : 1.15.2
  ionic (Ionic CLI) : 3.15.2
  
  local packages:
  @ionic/app-scripts : 3.0.0
  Ionic Framework    : ionic-angular 3.7.1
  
  System:
  Node : v6.11.2
  npm  : 5.4.2
  OS   : Windows 8.1
  
  Misc:
  backend : pro
  </code></pre>
  
  <p>Can somebody help me??
  Tyvm</p>