IOS Crash Report

I get t$$anonymous$$s crash at start . After 3-4 crashes the game works . I use Unity 5.1.1f1 Personal . Here is the symbolicated log :

 Incident Identifier: 04B26B85-FFC1-49C1-8158-36D80E4E4E5C
 CrashReporter Key:   b6f7c44d6205e7f94d7826718c4eff39d3321791
 Hardware Model:      iPhone6,1
 Process:             pampam [444]
 Path:                /private/var/mobile/Containers/Bundle/Application/CAFA9DEC-87CE-417A-97C0-1AE6723DBCF8/pampam.app/pampam
 Identifier:          com.digitype.pampam
 Version:             1.0 (1.0)
 Code Type:           ARM-64 (Native)
 Parent Process:      launchd [1]
 
 Date/Time:           2015-08-02 12:01:27.396 +0300
 Launch Time:         2015-08-02 12:01:24.997 +0300
 OS Version:          iOS 8.4 (12H143)
 Report Version:      105
 
 Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
 Exception Subtype: KERN_INVALID_ADDRESS at 0xff222c37ff222c57
 Triggered by Thread:  0
 
 Thread 0 name:  Dispatch queue: com.apple.main-thread
 Thread 0 Crashed:
 0   pampam                            0x00000001006dbd10 GpuProgramParameters::FindParam(ShaderLab::FastPropertyName const&, int*) const (GpuProgram.cpp:149)
 1   pampam                            0x000000010097a56c void ApplyMaterialPropertyBlockValuesMetal<SetValuesFunctorMetal>(MaterialPropertyBlock const&, GpuProgram*, GpuProgramParameters const*, ShaderType, SetValuesFunctorMetal&) (GpuProgramParamsApply.h:109)
 2   pampam                            0x00000001009771a4 GfxDeviceMetal::SetMaterialProperties(MaterialPropertyBlock const&) (GfxDeviceMetal.mm:514)
 3   pampam                            0x000000010065692c ApplyBuiltinInstanceProperty::PerformFlushMaterialProperties() (ApplyBuiltinInstanceProperty.cpp:13)
 4   pampam                            0x0000000100696c34 Skybox::SetupSun(Camera const&, GfxDevice&) (dynamic_array.h:292)
 5   pampam                            0x0000000100696eb0 Skybox::RenderSkybox(Unity::Material*, Camera const&) (Skybox.cpp:287)
 6   pampam                            0x000000010066a638 Camera::RenderSkybox() (Camera.cpp:796)
 7   pampam                            0x0000000100664b24 DoRenderLoop(RenderLoop&, RenderingPath, CullResults&, ShadowMapCache&, bool) (RenderLoopPrivate.cpp:435)
 8   pampam                            0x000000010066b4f8 Camera::DoRender(CullResults&, void (*)(Camera&, RenderLoop&, CullResults&), int) (Camera.cpp:1163)
 9   pampam                            0x000000010066bca8 Camera::Render(CullResults&, ShaderLab::ShaderPassContext&, int) (Camera.cpp:1867)
 10  pampam                            0x00000001006890c4 RenderManager::RenderCameras(int) (RenderManager.cpp:111)
 11  pampam                            0x0000000100757e04 PlayerRender(bool) (Player.cpp:1504)
 12  pampam                            0x000000010075870c PlayerLoop(bool, bool, IHookEvent*) (Player.cpp:1987)
 13  pampam                            0x000000010059da58 UnityPlayerLoopImpl(bool) (LibEntryPoint.mm:235)
 14  pampam                            0x000000010004908c UnityRepaint (UnityAppController+Rendering.mm:246)
 15  pampam                            0x0000000100059328 -[UnityAppController(ViewHandling) showGameUI] (UnityAppController+ViewHandling.mm:168)
 16  pampam                            0x0000000100056078 -[UnityAppController startUnity:] (UnityAppController.mm:112)
 17  Foundation                        0x000000018557417c __NSFireDelayedPerform + 420
 18  CoreFoundation                    0x0000000184638128 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 24
 19  CoreFoundation                    0x0000000184637dd8 __CFRunLoopDoTimer + 884
 20  CoreFoundation                    0x0000000184635824 __CFRunLoopRun + 1368
 21  CoreFoundation                    0x00000001845612d0 CFRunLoopRunSpecific + 392
 22  Grap$$anonymous$$csServices                  0x000000018dfbf6f8 GSEventRunModal + 164
 23  UIKit                             0x000000018915ef3c UIApplicationMain + 1484
 24  pampam                            0x00000001000431e0 main (main.mm:40)
 25  libdyld.dylib                     0x000000019699ea04 start + 0
 

Any ideas?