Crash in raycast/reading texture


I have a method using LineTraceSingle for raycasting, then reading the texture of the mesh hit, and calculating color in the position of hit.
I dont know exactly what part crashes because I just got a popup with the message:


UE log:

[2014.10.20-14.56.34:437] 15]LogD3D11RHI:Error: D3DRHI->GetDeviceContext()->Map(StagingTexture,0,D3D11_MAP_READ,0,&MappedTexture) failed 
 at D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.4\Engine\Source\Runtime\Windows\D3D11RHI\Private\D3D11Texture.cpp:1364 
[2014.10.20-14.57.04:106] 15]LogWindows: FPlatformMisc::RequestExit(1)

It doesnt happen at first click/raycast but 100% in a 10-20 seconds clicking.
Im using UE 4.4.
It is hardware related? I have an card from AMD Radeon HD 57xx series (I can check the exact type if necessary) and using newest safe catalyst driver.