UIFeedback Haptic Engine called more times than was activated
<p>I am using the <code>UIFeedback Haptic Engine</code> with <strong>swift 2.3</strong> like:</p>

<pre><code>let generator = UINotificationFeedbackGenerator()
generator.notificationOccurred(.Warning)
</code></pre>

<p>and</p>

<pre><code>let generator = UIImpactFeedbackGenerator(style: .Heavy)
generator.impactOccurred()
</code></pre>

<p>Today I got a new kind of error like this, and couldn't find the problem. Do you have any idea?</p>

<pre><code>UIFeedbackHapticEngine _deactivate] called more times than the feedback engine was activated
</code></pre>

<p>Details:</p>

<pre><code>Fatal Exception: NSInternalInconsistencyException
0  CoreFoundation                 0x1863e41c0 __exceptionPreprocess
1  libobjc.A.dylib                0x184e1c55c objc_exception_throw
2  CoreFoundation                 0x1863e4094 +[NSException raise:format:]
3  Foundation                     0x186e6e82c -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:]
4  UIKit                          0x18cc43fb8 -[_UIFeedbackEngine _deactivate]
5  UIKit                          0x18cad781c -[UIFeedbackGenerator __deactivateWithStyle:]
</code></pre>