Nexus 5 with Android 5.1.1 (LMY48M) restarts when an incoming call is rejected programmatically

I need to reject an incoming call in my app. I found this solution. Nexus 5 with Android 5.1.1 (LMY48M) and some other devices with 5.1.1 sometimes restart with the following exception. Did anybody experience that?

My compileSdkVersion is 23.

03-15 08:53:09.742 750-750/? E/AndroidRuntime: *** FATAL EXCEPTION IN SYSTEM PROCESS: main
                                               java.lang.NullPointerException
                                                   at com.android.internal.util.Preconditions.checkNotNull(Preconditions.java:37)
                                                   at com.android.server.telecom.Call.reject(Call.java:951)
                                                   at com.android.server.telecom.Call.processDirectToVoicemail(Call.java:747)
                                                   at com.android.server.telecom.Call.access$200(Call.java:63)
                                                   at com.android.server.telecom.Call$3.run(Call.java:176)
                                                   at android.os.Handler.handleCallback(Handler.java:739)
                                                   at android.os.Handler.dispatchMessage(Handler.java:95)
                                                   at android.os.Looper.loop(Looper.java:135)
                                                   at com.android.server.SystemServer.run(SystemServer.java:269)
                                                   at com.android.server.SystemServer.main(SystemServer.java:170)
                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                   at java.lang.reflect.Method.invoke(Method.java:372)
                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)