[BUG] NavlinkProxy blueprint cause tons of errors

Hello!

I create new blueprint and parent it from NavLinkProxy class. My blueprint looks like black square in Content Browser and log give to me tons of errors:

Address = 0xdde23e2f (filename not found) [in D:\UE4\4.3\Engine\Binaries\Win[2014.08.06-21.22.24:643][964]
LogUnrealMath:Error: FMatrix::Inverse(), trying to invert a NIL matrix, this results in NaNs! Use InverseSafe() instead.
[2014.08.06-21.22.24:647][964]LogOutputDevice: === Handled error: ===
Ensure condition failed: false [File:d:\buildfarm\buildmachine_++depot+ue4-releases+4.3\engine\source\runtime\core\public\math\UnrealMatrix.h] [Line: 268]
FMatrix::Inverse(), trying to invert a NIL matrix, this results in NaNs! Use InverseSafe() instead.
Stack: Address = 0xe4a5f996 (filename not found) [in D:\UE4\4.3\Engine\Binaries\Win64\UE4Editor-Core.dll]
Address = 0xe4915b01 (filename not found) [in D:\UE4\4.3\Engine\Binaries\Win64\UE4Editor-Core.dll]
Address = 0xe4915d47 (filename not found) [in D:\UE4\4.3\Engine\Binaries\Win64\UE4Editor-Core.dll]
Address = 0xddc91cbb (filename not found) [in D:\UE4\4.3\Engine\Binaries\Win64\UE4Editor-Renderer.dll]
Address = 0xdde568d2 (filename not found) [in D:\UE4\4.3\Engine\Binaries\Win64\UE4Editor-Renderer.dll]
Address = 0xdde6db61 (filename not found) [in D:\UE4\4.3\Engine\Binaries\Win64\UE4Editor-Renderer.dll]

Seems like everything else works correct!

LogUnrealMath:Error: FMatrix::Inverse(), trying to invert a NIL matrix, this results in NaNs! Use InverseSafe() instead.

I have a same Error. The editor sometimes crashs during play. The GameViewport turns black and strange messages fill my log. StarterContentEffects have no sounds etc… (Unreal Engine 4.4.2)

I don’t use any Matrix operations. Although I work on a methode using FMath::InterpEaseInOut and FRotator. https://forums.unrealengine.com/archive/index.php/t-33129.html FRotator seems to be the trigger.

Any advice how to avoid this problem?
thx

Problem solved. I had an Alpha > 1.